WO2021125247A1

WO2021125247A1 - Adhesive agent, adhesive tape, electrical appliance, onboard member, and securing method

Info

Publication number: WO2021125247A1
Application number: PCT/JP2020/047065
Authority: WO
Inventors: 寛幸片岡; 寛生山本; 絢足立; 知浩肥田
Original assignee: 積水化学工業株式会社
Priority date: 2019-12-18
Filing date: 2020-12-16
Publication date: 2021-06-24
Also published as: US20230043508A1; CN114829533A; JP2023036859A; EP4079517A1; KR20220115950A; JP7203244B2; JPWO2021125247A1; EP4079517A4

Abstract

An adhesive agent containing a polymer (X1) that contains at least 48 mass% of structural units derived from at least one monomer (Y) selected from the group consisting of monomers (A1) represented by general formula (1) and monomers (B1) represented by general formula (2), the adhesive agent being such that tanδ (23°C) derived using the expression G"(23°C)/G'(23°C) is 0.8-1.3, where G'(23°C) is the storage elastic modulus at 23°C, and G"(23°C) is the loss tangent at 23°C. In formula (1), R1 represents H or CH3, R2 represents -CnH2n+1, and n represents an integer of 7-14. In formula (2), R3 represents -C(=O)CmH2m+1, and m represents an integer of 7-13. The present invention thereby improves holding force at high temperatures, affixation properties at low temperatures, and adhesion to low-polarity adherends while raising the biological rate.

Description

Adhesives, adhesive tapes, appliances, in-vehicle components, and fixing methods

The present invention relates to an adhesive, an adhesive tape, an adhesive sheet, an adhesive, an electric appliance having an adhesive tape or an adhesive sheet, an in-vehicle member, and a fixing method using the adhesive or the adhesive tape.

Conventionally, an adhesive tape having an adhesive layer made of an adhesive has been widely used for fixing various parts in electric appliances, vehicles, houses, building materials, and the like. As the pressure-sensitive adhesive, a pressure-sensitive adhesive containing an acrylic polymer containing a constituent unit derived from an acrylic (meth) acrylate such as 2-ethylhexyl acrylate or n-butyl acrylate as a main component is known (for example, Patent Document 1, Patent Document 1, 2).

Japanese Unexamined Patent Publication No. 2015-021067 Japanese Unexamined Patent Publication No. 2015-120876

In recent years, due to the globalization of production bases of each company, assembly using adhesive tape has come to be performed in various environments. For example, products that require performance even in high-temperature environments, such as electrical appliances and in-vehicle components, may be assembled in cold regions, and the adhesive has high holding power at high temperatures and can be easily attached to the adherend even at low temperatures. Low temperature stickability may be required.

Low-temperature stickability requires high fluidity in a low-temperature environment, while in order to improve holding power in a high-temperature environment, cohesive force in a high-temperature environment is required. , It can be difficult to meet both of these characteristics. Furthermore, although it is generally difficult for adhesives to increase the adhesive strength of adherends with low polarity, many in-vehicle members and parts of electrical appliances have low polarity, such as polyolefin resins typified by polypropylene resin. Since they are used, it is necessary to increase the adhesive force to a low-polarity adherend in these applications.

On the other hand, the depletion of petroleum resources and the emission of carbon dioxide due to the combustion of petroleum-derived products are regarded as problems. Therefore, mainly in the medical field and the packaging material field, attempts have been made to save petroleum resources by using biological materials instead of petroleum-derived materials. Such attempts have spread to all fields, and the use of biological materials is also required in the fields of adhesives and adhesive tapes.

According to the studies by the present inventors, the acrylic pressure-sensitive adhesive containing a constituent unit derived from n-butyl acrylate, which is generally used in the past, has a holding power at a high temperature, a low-temperature stickability, a polyolefin resin, and the like. It has been found that any of the adhesive properties to low-polarity adherends can be improved. However, alkyl (meth) acrylates having a small number of carbon atoms, such as n-butyl acrylate, are produced from petroleum and cannot sufficiently improve the carbon content (that is, bio-rate) derived from living organisms.

Therefore, the present invention provides an adhesive and an adhesive sheet capable of improving the holding power at high temperature, the low temperature stickability, and the adhesiveness to a low-polarity adherend such as a polyolefin resin while increasing the biorate. The challenge is to provide.

As a result of diligent studies, the present inventors have found that the above problems can be solved by setting the monomer component of the polymer used for the pressure-sensitive adhesive to a predetermined value and setting tan δ (23 ° C.) within a specific range. The following invention has been completed. That is, the gist of the present invention is the following [1] to [32].
[1] Derived from at least one monomer (Y) selected from the group consisting of the monomer (A1) represented by the following general formula (1) and the monomer (B1) represented by the following general formula (2). Contains a polymer (X1) containing 48% by mass or more of a constituent unit,
Assuming that the storage elastic modulus at 23 ° C. is G'(23 ° C.) and the loss elastic modulus is G "(23 ° C.), tan δ (23 ° C.) obtained by G" (23 ° C.) / G'(23 ° C.) is 0. .8-1.3 adhesives.

In formula (1), R ¹ represents H or CH ₃ , R ² represents −C _n H _{2n + 1} , and n represents an integer of 7 to 14. In equation (2), R ³ represents −C (= O) C _m H _{2m + 1} , and m represents an integer of 6 to 13.
[2] The pressure-sensitive adhesive according to the above [1], wherein the polymer (X1) has a weight average molecular weight of 200,000 to 1,000,000.
[3] The pressure-sensitive adhesive according to the above [1] or [2], which has a degree of cross-linking of 10 to 70%.
[4] Assuming that the storage elastic modulus at 0 ° C. is G'(0 ° C.), any one of the above [1] to [3] in which logG'(0 ° C.) [Pa] is 5.0 to 6.5. One of the adhesives listed.
[5] Assuming that the storage elastic modulus at 23 ° C. is G'(23 ° C.), log G'(23 ° C.) [Pa] is 4.8 to 5.5, and any one of the above [1] to [4]. Adhesives listed in 1.
[6] Assuming that the storage elastic modulus at 80 ° C. is G'(80 ° C.), the log G'(80 ° C.) [Pa] is 4.1 to 4.8, as described in [1] to [5] above. The adhesive according to any one.
[7] The pressure-sensitive adhesive according to any one of the above [1] to [6], wherein the glass transition temperature (Tg) is 15 ° C. or lower.
[8] The pressure-sensitive adhesive according to any one of the above [1] to [7], wherein the content of carbon derived from an organism is 40% by mass or more.
[9] The pressure-sensitive adhesive according to any one of the above [1] to [8], which further comprises a pressure-sensitive adhesive.
[10] An adhesive tape provided with an adhesive layer made of the adhesive according to any one of the above [1] to [9].
[11] The adhesive tape according to the above [10], further comprising a base material, wherein the pressure-sensitive adhesive layer is provided on at least one surface of the base material.
[12] The adhesive tape according to the above [11], wherein the base material is any one selected from a non-woven fabric, a polyethylene terephthalate film, and a foam.
[13] An electric appliance is constructed by using the adhesive according to any one of the above [1] to [9] or the adhesive tape according to any one of the above [10] to [12]. A fixing method for fixing a part or an in-vehicle member.
[14] The pressure-sensitive adhesive according to any one of the above [1] to [9] is provided, and the peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by gel permeation chromatography (GPC) is 137,000 or more and 300,000 or less. A pressure-sensitive adhesive sheet in which the sol content (R _sol ) of the pressure-sensitive adhesive is 90% by mass or less, and the glass transition temperature (Tg) of the pressure-sensitive adhesive is 5 ° C. or less.
[15] The pressure-sensitive adhesive sheet according to the above [14], wherein the hardness (S) represented by the following general formula (3) in the pressure-sensitive adhesive is 50,000 or more and 180,000 or less.
S = Mw × R _sol / D (3)
In the formula (3), Mw represents the weight average molecular weight of the sol of the pressure-sensitive adhesive by GPC, R _sol represents the sol content of the pressure-sensitive adhesive, and D represents the dispersity of the sol of the pressure-sensitive adhesive by GPC. Represent.
[16] The pressure-sensitive adhesive sheet according to the above [14] or [15], wherein the dispersity (D) of the sol of the pressure-sensitive adhesive by GPC is 1.6 or more and less than 3.
[17] The pressure-sensitive adhesive sheet according to any one of the above [14] to [16], wherein the weight average molecular weight (Mw) of the sol of the pressure-sensitive adhesive by GPC is 190,000 or more and 700,000 or less.
[18] The pressure-sensitive adhesive sheet according to any one of the above [14] to [17], _{wherein the sol fraction (R sol) of the pressure-sensitive adhesive is 45% by mass or more and 75% by mass or less.}
[19] The pressure-sensitive adhesive sheet according to any one of the above [14] to [18], wherein the glass transition temperature (Tg) of the pressure-sensitive adhesive is 2.5 ° C. or lower.
[20] The pressure-sensitive adhesive sheet according to any one of the above [14] to [19], wherein the bio-rate of the pressure-sensitive adhesive is 51% or more.
[21] The pressure-sensitive adhesive sheet according to the above [20], wherein the content of the structural unit derived from n-heptyl (meth) acrylate in the polymer (X1) is 48% by mass or more.
[22] A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive containing a biological component, wherein the peak top molecular weight (Mtp) of the sol component of the pressure-sensitive adhesive by gel permeation chromatography (GPC) is 137,000 or more and 300,000 or less, and the pressure-sensitive adhesive. A pressure-sensitive adhesive sheet having a sol content (R _sol ) of 90% by mass or less and a glass transition temperature (Tg) of the pressure-sensitive adhesive of 5 ° C. or less.
[23] The pressure-sensitive adhesive sheet according to the above [22], wherein the hardness (S) represented by the following general formula (3) in the pressure-sensitive adhesive is 50,000 or more and 180,000 or less.
S = Mw × R _sol / D (3)
In the formula (3), Mw represents the weight average molecular weight of the sol of the pressure-sensitive adhesive by GPC, R _sol represents the sol content of the pressure-sensitive adhesive, and D represents the dispersity of the sol of the pressure-sensitive adhesive by GPC. Represent.
[24] The pressure-sensitive adhesive sheet according to the above [22] or [23], wherein the dispersity (D) of the sol of the pressure-sensitive adhesive by GPC is 1.6 or more and less than 3.
[25] The pressure-sensitive adhesive sheet according to any one of the above [22] to [24], wherein the weight average molecular weight (Mw) of the sol of the pressure-sensitive adhesive by GPC is 190,000 or more and 700,000 or less.
[26] The pressure-sensitive adhesive sheet according to any one of the above [22] to [25], _{wherein the sol fraction (R sol) of the pressure-sensitive adhesive is 45% by mass or more and 75% by mass or less.}
[27] The pressure-sensitive adhesive sheet according to any one of the above [22] to [26], wherein the glass transition temperature (Tg) of the pressure-sensitive adhesive is 2.5 ° C. or lower.
[28] The pressure-sensitive adhesive sheet according to any one of claims 22 to 27, wherein the pressure-sensitive adhesive has a bio-rate of 51% or more.
[29] The pressure-sensitive adhesive is at least one monomer selected from the group consisting of the monomer (A2) represented by the following general formula (4) and the monomer (B2) represented by the following general formula (5). The pressure-sensitive adhesive sheet according to any one of the above [22] to [28], which contains a polymer (X2) containing a structural unit derived from (Y2) in an amount of 48% by mass or more.

In formula (4), R ⁴ represents H or CH ₃ , R ⁵ represents -C _n H _{2n + 1} , n represents an integer of 7 to 20, and in formula (5) R ⁶ represents -C (=). O) C _m H _{represents 2m + 1} , and m represents an integer of 6 to 13.
[30] The pressure-sensitive adhesive sheet according to the above [29], wherein the content of the structural unit derived from n-heptyl (meth) acrylate in the polymer (X2) is 48% by mass or more.
[31] The adhesive according to any one of the above [1] to [9], the adhesive tape according to any one of the above [10] to [12], or the above [14] to [30]. ] The electric appliance provided with the adhesive sheet according to any one of.
[32] The adhesive according to any one of the above [1] to [9], the adhesive tape according to any one of the above [10] to [12], or the above [14] to [30]. An in-vehicle member including the adhesive sheet according to any one of the above.

According to the pressure-sensitive adhesive and the pressure-sensitive adhesive sheet of the present invention, all of the holding power at high temperature, the low-temperature stickability, and the adhesiveness to a low-polarity adherend are improved while increasing the bio-rate.

The outline of the cohesive force test using the minute shear displacement displacement measurement test apparatus, and the enlarged view of the part A are shown.

<< First Invention >>
Hereinafter, the first invention of the present invention will be described in detail using embodiments.
<Adhesive>
[Polymer (X1)]
The pressure-sensitive adhesive of the present invention contains a polymer (X1). The polymer (X1) is at least one monomer (Y1) selected from the group consisting of the monomer (A1) represented by the following general formula (1) and the monomer (B1) represented by the following general formula (2). ) Derived from the constituent units. In addition, in this specification, the term "monomer (Y1)" is also used to collectively explain a monomer (A1) and a monomer (B1).

In formula (1), R ¹ represents H or CH ₃ , R ² represents −C _n H _{2n + 1} , and n represents an integer of 7-14. In equation (2), R ³ represents −C (= O) C _m H _{2m + 1} , and m represents an integer of 6 to 13.

In the present invention, by containing at least one of the monomer (A1) and the structural unit derived from the monomer (B1), it becomes easy to adjust tan δ (23 ° C.), which will be described later, to an appropriate range, and the holding power at a high temperature can be easily adjusted. , Low temperature stickability, and adhesion to low-polarity adherends are also facilitated. In addition, the monomer (A1) and the monomer (B1) can be easily produced from biological raw materials, and the biorate, which will be described later, can be easily increased.

The polymer (X1) may contain a structural unit derived from one or both of the monomer (A1) and the monomer (B1), but preferably contains a structural unit derived from the monomer (A1). When the polymer (X1) has a structural unit derived from the monomer (A1), it becomes easy to adjust tan δ (23 ° C.) within a desired range, and it also has a holding power at a high temperature, a low temperature stickability, and a low polarity. Adhesion to the adherend is also easily improved.

The alkyl group ^{of R 2} in the formula (1) _{(-C n} H _{2n + 1} ) and the alkyl group ^{of R 3} in the formula (2) _{(-C m} H _{2m + 1} ) may be linear or branched. However, a linear chain is preferable from the viewpoint of facilitating the range of tan δ (23 ° C.) to an appropriate range. Further, from the viewpoint of facilitating the range of tan δ (23 ° C.) to an appropriate range, ^{n in R 2} is preferably 7 to 10, and more preferably 7. Further, from the viewpoint of improving the adhesive performance, it is preferable that ^{R 1 is H in the formula (1).}
Therefore, the polymer (X1) preferably contains a structural unit derived from the monomer (A1) in which n in the general formula (1) is 7 to 10 and R ^{2 is linear, and n is 7.} Moreover, it is more preferable to contain a structural unit derived from the monomer (A1) in which R ² is linear, and it is further preferable that ^{R 1 is H in the monomer (A1) in this case.}

Specific examples of the monomer (A1) include n-heptyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, n-decyl (meth) acrylate, and 2-octyl (meth). Examples thereof include acrylate, n-nonyl (meth) acrylate, undecyl (meth) acrylate, tetradecyl (meth) acrylate, and myristyl (meth) acrylate. These monomers (A1) may be used alone or in combination of two or more.
Specific examples of the monomer (B1) include vinyl caprate, vinyl laurate, vinyl caprylate, vinyl nonanoate and the like. These monomers (B1) may be used alone or in combination of two or more.
Among the above-mentioned monomers (A1) and (B1), n-heptyl (meth) acrylate is preferable, and n-heptyl acrylate is more preferable. The use of n-heptyl (meth) acrylates tends to improve retention at high temperatures, low temperature stickability, and adhesion to low polarity adherends by keeping tan δ (23 ° C.) in the appropriate range. Become.
In addition, in this specification, (meth) acrylate is used as a term meaning one or both of acrylate and methacrylate, and other similar terms are also used.

Further, in the above general formulas (1) and (2), R ² and R ³ are preferably carbons derived from living organisms. By using ^{carbon of biological origin for R 2} and R ³ , the biorate described later can be increased. Monomers (A1) and (B1), each of which is a biological carbon in R ² and R ^3, are obtained by using saturated fatty acids or unsaturated fatty acids collected from animals and plants as raw materials, and alcoholizing and esterifying them. It is inexpensive and easily available.

In the present invention, the content of the structural unit derived from the monomer (Y1) (that is, at least one monomer selected from the monomer (A1) and the monomer (B1)) is 48% by mass or more in the polymer (X1). If this content is less than 48% by mass, it becomes difficult to adjust tan δ (23 ° C.) to an appropriate range. In addition, it becomes difficult to improve the holding power at high temperature, the low temperature stickability, and the adhesiveness to a low-polarity adherend while increasing the bio-rate.
From the viewpoint of adjusting tan δ (23 ° C.) within a desired range and improving the various performances described above while increasing the biorate, the content of the structural unit derived from the monomer (Y1) is 70% by mass or more. Is preferable, 80% by mass or more is more preferable, and 90% by mass or more is further preferable. The content of the structural unit derived from the monomer (Y1) is preferably 99% by mass or less, more preferably 98% by mass or less, and 97.5% by mass, for example, in order to contain a predetermined amount of the functional group-containing monomer described later. The following is more preferable.

Further, as described above, the monomer (A1) preferably contains n-heptyl (meth) acrylate. The content of the structural unit derived from n-heptyl (meth) acrylate in the polymer (X1) is 48% by mass or more from the viewpoint of tan δ (23 ° C.) and from the viewpoint of improving the various performances described above while increasing the biorate. Is more preferable, 70% by mass or more is more preferable, 80% by mass or more is further preferable, and 90% by mass or more is particularly preferable. The content of the structural unit derived from n-heptyl (meth) acrylate is preferably 99% by mass or less, more preferably 98% by mass or less, and further preferably 97.5% by mass or less.

The polymer (X1) preferably contains a structural unit derived from another monomer other than the above-mentioned monomer (A1) and monomer (B1). The other monomer is preferably a monomer having a polymerizable carbon-carbon double bond such as a vinyl group and a (meth) acryloyl group. As the other monomer, a monomer containing a polar group (hereinafter, also referred to as “polar group-containing monomer (C)”) is preferable. Since the polymer (X1) contains a structural unit derived from the polar group-containing monomer (C), it becomes easy to increase the adhesive strength of the pressure-sensitive adhesive, which provides holding power at high temperature, low-temperature stickability, and low-polarity adherend. It becomes easy to improve the adhesiveness to the surface.
The polar group is a functional group having an active hydrogen, and specific examples thereof include a carboxy group, a hydroxyl group, an amino group, and an amide group. The polar group may be a functional group capable of reacting with a cross-linking agent described later. The polar group-containing monomer (C) may be used alone or in combination of two or more.
Examples of the polar group-containing monomer (C) include a carboxy group-containing monomer (hereinafter, also referred to as “carboxy group-containing monomer (C1)”) and a hydroxyl group-containing monomer (hereinafter, “hydroxyl group-containing monomer (C2)”). It is preferable to contain any of these), and it is more preferable to use these in combination.

Examples of the carboxy group-containing monomer (C1) include acrylic acid, methacrylic acid, crotonic acid and the like. Among these, at least one selected from the group consisting of acrylic acid and methacrylic acid is preferable, and acrylic acid is more preferable.
The content of the structural unit derived from the carboxy group-containing monomer (C1) in the polymer (X1) is preferably 0.5 to 10% by mass. By setting the content of the constituent unit derived from (C1) within the above range, the adhesive strength of the pressure-sensitive adhesive is appropriately increased, and the holding power at high temperature, low-temperature stickability, and adhesion to a low-polarity adherend are obtained. It becomes easier to improve the sex. From these viewpoints, the content of the structural unit derived from the carboxy group-containing monomer (C1) is more preferably 1 to 8% by mass, further preferably 2 to 6% by mass.

Examples of the hydroxyl group-containing monomer (C2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxy. Examples thereof include (meth) acrylate having a hydroxyl group such as butyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate, and allyl alcohol. Among these, (meth) acrylate having a hydroxyl group is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

The content of the structural unit derived from the hydroxyl group-containing monomer (C2) in the polymer (X1) is preferably 0.1 to 15% by mass, preferably 0.05 to 10% by mass, from the viewpoint of improving various performances of the pressure-sensitive adhesive. , 0.1-5% by mass is more preferable. The hydroxyl group-containing monomer (C2) is preferably used in combination with the carboxy group-containing monomer (C1), and the content of the structural unit derived from the hydroxyl group-containing monomer (C2) when used in combination is 0.01 to 5% by mass. Is preferable, 0.05 to 2% by mass is more preferable, and 0.1 to 0.9% by mass is further preferable. When used in combination with a carboxy group-containing monomer (C1), the adhesive strength of the adhesive can be improved even in a small amount in this way, and the holding power at high temperature, low temperature stickability, and adhesiveness to low-polarity adherends can be improved. It becomes easy to improve.

Examples of the monomer containing an amide group include isopropyl (meth) acrylamide and dimethylaminopropyl (meth) acrylamide.
As the monomer other than the monomers (A1) and (B1), a monomer other than the functional group-containing monomer may be used, and an alkyl (meth) acrylate other than the compound represented by the general formula (1) can be mentioned. Examples of such alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, and n-hexyl (meth) acrylate. ) Alkyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, 5,7,7-trimethyl-2- (1,3,3-trimethyl) having 1 to 6 carbon atoms in an alkyl group such as acrylate. Examples thereof include alkyl (meth) acrylates having about 15 to 24 carbon atoms such as esters of butyl) octanol-1 and (meth) acrylic acid, behenyl (meth) acrylates, and arachidyl (meth) acrylates.
In addition, examples of other monomers include aromatics such as (meth) acrylate having an alicyclic structure such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, benzyl (meth) acrylate, and 2-phenoxyethyl (meth) acrylate. (Meta) acrylate having a ring, monomer having an epoxy group such as glycidyl (meth) acrylate, monomer having a nitrile group such as (meth) acrylonitrile, 2-butoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, Examples include styrene.
Monomers other than the polar group-containing monomer may be used alone or in combination of two or more.
The other monomer preferably contains carbon derived from a living organism from the viewpoint of improving the biorate, which will be described later, but may be a monomer derived from petroleum without containing carbon derived from a living organism.

The weight average molecular weight (Mw) of the polymer (X1) is preferably 200,000 to 1,000,000.
When the weight average molecular weight (Mw) is 200,000 or more, the shear strength of the pressure-sensitive adhesive can be increased and the holding power of the pressure-sensitive adhesive under high temperature can be increased. Further, when it is set to 1 million or less, the adhesive strength of the pressure-sensitive adhesive is improved, and it becomes easy to improve the low-temperature adhesiveness, the adhesiveness to a low-polarity adherend, and the like.
From these viewpoints, the weight average molecular weight (Mw) is more preferably 300,000 or more, further preferably 400,000 or more, still more preferably 900,000 or less, still more preferably 800,000 or less.
The weight average molecular weight (Mw) can be appropriately adjusted by appropriately selecting the amount of the polymerization initiator used, the polymerization conditions such as the polymerization temperature, the polymerization method, and the like.
The weight average molecular weight is a standard polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

The polymer (X1) is the main component of the adhesive. The content of the polymer (X1) in the pressure-sensitive adhesive is, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 65% by mass or more in order to impart appropriate adhesive performance. Further, the polymer (X1) in the pressure-sensitive adhesive is preferably 99% by mass or less, and further 95% by mass or less so that a predetermined amount of components other than the polymer (X1) such as a tackifier and a cross-linking agent can be blended in the pressure-sensitive adhesive. It is preferable, and more preferably 92% by mass or less.

(Manufacturing method of polymer (X1))
The polymer (X1) can be obtained by radically reacting a mixture of the above-mentioned raw material monomers in the presence of a polymerization initiator.
The radical reaction method is not particularly limited, and examples thereof include living radical polymerization and free radical polymerization. According to the living radical polymerization, a copolymer having a more uniform molecular weight and composition as compared with the free radical polymerization can be obtained, the formation of low molecular weight components and the like can be suppressed, and the cohesive force of the pressure-sensitive adhesive is increased. .. The polymerization method is not particularly limited, and conventionally known methods can be used. Examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like. Of these, solution polymerization is preferable because it is easy to synthesize.

When solution polymerization is used as the polymerization method, examples of the reaction solvent include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether and the like. These reaction solvents may be used alone or in combination of two or more.

The above-mentioned polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds. Examples of the organic peroxide include 1,1-bis (t-hexyl peroxy) -3,3,5-trimethylcyclohexane, t-hexyl peroxypivalate, t-butylperoxypivalate, 2,5. -Dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Examples thereof include isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate and t-butylperoxylaurate. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

Further, in the case of living radical polymerization, examples of the above-mentioned polymerization initiator include an organic tellurium polymerization initiator. The organic telluride polymerization initiator is not particularly limited as long as it is generally used for living radical polymerization, and examples thereof include organic telluride compounds and organic telluride compounds. In the living radical polymerization, in addition to the organic tellurium polymerization initiator, an azo compound may be used as the polymerization initiator for the purpose of promoting the polymerization rate.

[Adhesive imparting agent]
The pressure-sensitive adhesive of the present invention preferably contains a pressure-sensitive adhesive in addition to the polymer (X1). By containing the tackifier, the stickiness of the pressure-sensitive adhesive is improved. In addition, it becomes easy to improve the adhesiveness to a low-polarity adherend. Further, for example, by adding a tackifier so that the glass transition temperature (Tg) is equal to or lower than the upper limit value described later, the low temperature stickability is improved.
Examples of the tackifier include rosin-based resins such as rosin-based resins and polymerized rosin-ester resins, rosin-based tackifiers such as hydrogenated rosin-based resins, and terpene-based adhesives such as terpene-based resins and terpene phenol-based resins. Examples thereof include an imparting agent, a Kumaron inden-based resin, an alicyclic saturated hydrocarbon-based resin, a C5-based petroleum resin, a C9-based petroleum resin, and a C5-C9 copolymer-based petroleum resin. These tackifier resins may be used alone or in combination of two or more.

Among the above, rosin-based tackifiers and terpene-based tackifiers are preferable. These tackifiers can be easily synthesized from biological raw materials, and the biorate can be easily improved. For example, the rosin-based tackifier is derived from a natural resin such as pine fat, and the terpene-based tackifier is derived from plant essential oils and the like. Further, as the tackifier, a rosin-based tackifier is particularly suitable. By using the rosin-based tackifier, it becomes easy to improve the adhesiveness to a low-polarity adherend such as a polyolefin resin typified by polypropylene resin.

The softening point of the tackifier is preferably 120 ° C. or higher. The above-mentioned polymer (X1) tends to have a relatively low glass transition temperature and tends to have a low holding power at high temperatures, but when used in combination with a tackifier having a relatively high softening point, it has a holding power at high temperatures. Can be prevented from becoming low. From such a viewpoint, the softening point of the tackifier is more preferably 130 ° C. or higher, further preferably 140 ° C. or higher. The softening point of the pressure-sensitive adhesive is preferably 165 ° C. or lower, more preferably 160 ° C. or lower, and even more preferably 155 ° C. or lower, from the viewpoint of imparting appropriate adhesive performance to the pressure-sensitive adhesive. The softening point can be measured according to JIS K2207.

When the pressure-sensitive adhesive contains a pressure-sensitive adhesive, the content of the pressure-sensitive adhesive is not particularly limited, but is preferably 10 to 50 parts by mass with respect to 100 parts by mass of the polymer (X1). When the content of the tackifier is at least the above lower limit value, it becomes easy to improve the low-temperature adhesiveness and the adhesiveness to a low-polarity adherend. Further, by setting it to the above upper limit value or less, it is possible to prevent the holding power from being lowered at a high temperature. From the above viewpoint, the content of the tackifier is more preferably 12 to 40 parts by mass, further preferably 15 to 35 parts by mass, and particularly preferably 18 to 30 parts by mass.

[Crosslinking agent]
The pressure-sensitive adhesive of the present invention preferably contains a cross-linking agent and is cross-linked. That is, the pressure-sensitive adhesive is preferably one obtained by cross-linking a pressure-sensitive adhesive composition containing a cross-linking agent in addition to the above-mentioned polymer (X1) or polymer (X1) and a pressure-sensitive adhesive. The cross-linking agent may cross-link the pressure-sensitive adhesive, for example, by reacting with the polar group of the polymer (X1).
Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and metal chelate-based cross-linking agents. Among these, at least one selected from the group consisting of an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent is preferable, and an isocyanate-based cross-linking agent is more preferable.

The isocyanate-based cross-linking agent is not particularly limited as long as it is a compound having two or more isocyanate groups in one molecule. For example, tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 1,5-naphthalenedisocyanate, diphenylmethane diisocyanate. , Isophorone diisocyanate, xylene diisocyanate, tolylene diisocyanate adduct of trimethylolpropane and the like. Among these, tolylene diisocyanate and trimethylolpropane tolylene diisocyanate adducts are preferable.
Commercially available isocyanate-based cross-linking agents include various polyisocyanate compounds such as Coronate L-45 and Coronate L-55E (manufactured by Toso), Buret polyisocyanate compounds such as Sumijour N (manufactured by Sumitomo Bayer Urethane), and Death. Polyisocyanate compounds having an isocyanurate ring such as module IL, HL (manufactured by Bayer AG), coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.), Sumijour L (manufactured by Sumitomo Bayer Urethane Co., Ltd.), Coronate L, Coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.) ) And the like, such as adduct polyisocyanate compounds.

The epoxy-based cross-linking agent is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule, and for example, diglycidyl aniline, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether. 1,6-Hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylpropan triglycidyl ether, 1,3-bis (N, N-diglycidyl aminoethyl) cyclohexane, N, N, N', N'- Examples thereof include tetraglycidyl-m-xylene diamine.
Examples of commercially available epoxy-based cross-linking agents include E-AX and E-5C (manufactured by Soken Chemical Co., Ltd.).
One type of cross-linking agent may be used alone, or two or more types may be used in combination.

The blending amount of the cross-linking agent in the pressure-sensitive adhesive may be appropriately changed according to the type of the polymer (X1), desired physical properties such as the degree of cross-linking, etc., but is, for example, 0.1 with respect to 100 parts by mass of the polymer (X1). It is about 20 parts by mass, preferably 0.4 to 8 parts by mass, and more preferably 0.7 to 4 parts by mass.

(Crosslink degree)
The degree of cross-linking of the pressure-sensitive adhesive of the present invention is preferably 10 to 70%. By setting the degree of cross-linking within the above range, it becomes easy to improve the holding power at high temperature, the low temperature stickability, the adhesiveness to a low-polarity adherend, and the like. From such a viewpoint, the degree of cross-linking of the pressure-sensitive adhesive is more preferably 20% or more, further preferably 30% or more, still more preferably 60% or less, still more preferably 50% or less. The degree of cross-linking of the pressure-sensitive adhesive is indicated by the gel fraction, and the measuring method thereof is as shown in Examples. The degree of cross-linking of the pressure-sensitive adhesive can be appropriately adjusted by changing the blending amount of the cross-linking agent or the like.

[Other additives]
The pressure-sensitive adhesive of the present invention may contain additives such as a silane coupling agent, an antioxidant, an ultraviolet inhibitor, a plasticizer, an emulsifier, a softening agent, a filler, a pigment, and a dye, if necessary. Good. As these additives, it is preferable to select a biological material as much as possible from the viewpoint of increasing the biorate.

<Storage modulus>
(Tanδ (23 ° C))
The pressure-sensitive adhesive of the present invention is G "(23 ° C.) / G'(23 ° C.), where G'(23 ° C.) is the storage elastic modulus at 23 ° C. and G" (23 ° C.) is the loss elastic modulus at 23 ° C. ) Is tan δ (23 ° C.) of 0.8 to 1.3. When tan δ (23 ° C.) is less than 0.8 or more than 1.3, all of the holding power at high temperature, low temperature stickability, and adhesiveness to low-polarity adherends such as polyolefin resin are exhibited. It becomes difficult to meet. From these viewpoints, tan δ (23 ° C.) is preferably 0.85 or more, more preferably 0.88 or more, preferably 1.2 or less, more preferably 1.1 or less, and further preferably 1.0 or less. ..

tan [delta (23 ° C.), the kind of the monomer component used in the polymer (X1), can be adjusted by such an amount, for example, monomers (A1), (B1) Equation (1) of, ^R 2, R in (2) ^{By making 3} linear or reducing the values of n and m, tan δ (23 ° C.) tends to increase. Further, by adjusting the tackifier resin and the monomer composition and setting the glass transition temperature (Tg) in the range of -255 to 15 ° C., it becomes easy to adjust the tan δ (23 ° C.) within the desired range. It can also be adjusted by the molecular weight of the polymer (X1). For example, when the molecular weight of the polymer (X1) is reduced, the value of tan δ (23 ° C.) tends to decrease.

(Storage modulus at 23 ° C)
Assuming that the storage elastic modulus at 23 ° C. is G'(23 ° C.), logG'(23 ° C.) [Pa] is preferably 4.8 to 5.5. By setting logG'(23 ° C.) [Pa] within the above range, the adhesive properties at room temperature can be improved, and for example, the adhesiveness to a low-polarity adherend at room temperature can be easily improved. From this point of view, logG'(23 ° C.) [Pa] is more preferably 4.85 to 5.4, still more preferably 4.9 to 5.3.

(Storage modulus at 80 ° C)
Assuming that the storage elastic modulus at 80 ° C. is G'(80 ° C.), logG'(80 ° C.) [Pa] is preferably 4.1 to 4.8. By setting logG'(80 ° C.) [Pa] within the above range, the cohesive force at high temperature and the like can be improved, and the adhesiveness and holding power at high temperature can be improved. From this point of view, logG'(80 ° C.) [Pa] is more preferably 4.15 to 4.75, and even more preferably 4.2 to 4.7.

(Storage modulus at 0 ° C)
Assuming that the storage elastic modulus at 0 ° C. is G'(0 ° C.), logG'(0 ° C.) [Pa] is preferably 5.0 to 6.5. By setting logG'(0 ° C.) [Pa] within the above range, it becomes easy to improve the low temperature stickability. From such a viewpoint, logG'(0 ° C.) [Pa] is more preferably 5.4 to 6.4, still more preferably 5.5 to 6.3.
Note that logG'(0 ° C.) [Pa] means the logarithm of the storage elastic modulus represented by the unit "Pa". Other similar expressions are synonymous.

The storage elastic modulus G'at 0 ° C., 23 ° C., and 80 ° C. can be adjusted by the type and amount of the monomer component used in the polymer (X1). By setting the content and the like as described above, it becomes easy to adjust within the above range. Further, the storage elastic modulus G'at each temperature can be adjusted by the weight average molecular weight and the degree of cross-linking. For example, when the weight average molecular weight and the degree of cross-linking are increased, the storage elastic modulus G'at each temperature tends to increase. Furthermore, it can be adjusted by the molecular weight distribution. For example, the storage elastic modulus G'tends to increase when the molecular weight distribution is narrowed and to decrease when the molecular weight distribution is widened.

(Glass transition temperature (Tg))
The glass transition temperature (Tg) of the pressure-sensitive adhesive of the present invention is preferably 15 ° C. or lower. By setting the temperature to 15 ° C. or lower, tan δ (23 ° C.) can be easily increased, and the holding power at high temperature and the low temperature stickability can be easily improved. From these viewpoints, the glass transition temperature (Tg) is preferably 10 ° C. or lower, more preferably 5 ° C. or lower. The glass transition temperature (Tg) of the pressure-sensitive adhesive is not particularly limited, but from the viewpoint of improving the holding power at high temperatures, for example, −40 ° C. or higher, preferably −28 ° C. or higher, more preferably −25 ° C. or higher, and further. It is preferably −20 ° C. or higher.
The glass transition temperature (Tg) can be adjusted by the type and amount of the monomers constituting the polymer (X1). The type and amount of the tackifier can also be adjusted. For example, by using a tackifier having a high softening point or increasing the amount of the tackifier, the glass transition temperature (Tg) can be adjusted. Is likely to be high. The glass transition temperature (Tg) can also be adjusted by adding fine particles or the like.

The storage elastic modulus G'and the loss elastic modulus G'at each of the above temperatures are values obtained by measuring under the measurement conditions described in Examples described later using a polymer dynamic viscoelasticity measuring device. (23 ° C.) is a value obtained from the measured storage elastic modulus G'(23 ° C.) and loss elastic modulus G "(23 ° C.) at 23 ° C. Further, the glass transition temperature (Tg) is measured by using a polymer dynamic viscoelasticity measuring device under the measurement conditions described in Examples described later.

(Bio rate)
The pressure-sensitive adhesive of the present invention preferably has a carbon content of biological origin (hereinafter, also referred to as "bio-rate") of 40% by mass or more. Generally, a bio-rate of 40% by mass or more is a guideline for a "bio-based product". Bio-based products can save petroleum resources by using renewable organic resources, reduce carbon dioxide emissions from combustion of petroleum-derived products, and reduce the burden on the environment. From these viewpoints, the biorate is more preferably 50% by mass or more, and further preferably 60% by mass or more. Further, the higher the bio-rate, the better, and it may be 100% by mass or less.
Biological carbon contains a certain proportion of radioactive isotopes (C-14), whereas petroleum-derived carbon contains almost no C-14. Therefore, the biorate can be calculated by measuring the concentration of C-14 contained in the pressure-sensitive adhesive or the pressure-sensitive adhesive tape described later. Specifically, it can be measured according to ASTM D6866, which is a standard used in many bioplastic industries.

(Tack value)
The pressure-sensitive adhesive of the present invention preferably has a peeling limit value of 400 gf · s or more of the pressure-sensitive adhesive tape at 23 ° C. measured by a tack test. The tack test is performed as follows.
First, the adhesive tape is placed on a plate of a tack tester (for example, TAC-1000 manufactured by Reska Co., Ltd.) set at 23 ° C. with the adhesive layer facing up. The non-measurement surface of the adhesive tape is lined with a film such as a polyethylene terephthalate (PET) film. Next, a cylindrical stainless steel probe having a diameter of 5 mm is pressed against the adhesive tape at a probe temperature of 23 ° C., a pressing speed of 2 mm / s, and a pressing load of 100 gf, and is held in that state for 0.1 seconds. After that, the probe is pulled up at a pulling speed of 0.2 mm / s. The force applied to the adhesive tape during this period is measured.
In the above description, an example in which the adhesive constitutes the adhesive tape has been described, but even when the adhesive does not form the adhesive, the adhesive is similarly placed on the plate set at 23 ° C. of the tack tester. It is good to measure in the same way.

_{The peeling limit value is an integral from the time T 1 at} which the force indicates 0 to the time at which the maximum force (peak top) is indicated in the force-time curve indicating the force applied to the adhesive tape at 23 ° C. measured by the tack test. Means a value. In the tack test, when the probe is pressed against the adhesive tape, the force-time curve goes down, and then when the probe is started to be pulled up, the force-time curve goes up. _{The integrated value from the time T 1 at} which the force indicates 0 to the _{time T 2} at which the maximum force (peak top) is indicated is calculated, and this is used as the peeling limit value.
By adjusting the peeling limit value to the above range, peeling of the adhesive tape can be suppressed even under a high temperature and high humidity condition and a situation where a restoring force is applied. The preferable lower limit of the peeling limit value is 450 gf · s, and the more preferable lower limit is 500 gf · s. Further, the upper limit of the peeling limit value is not particularly limited.

(Preparation of adhesive)
The pressure-sensitive adhesive of the present invention may be formed from, for example, a pressure-sensitive adhesive composition prepared. The pressure-sensitive adhesive composition comprises components for forming a pressure-sensitive adhesive, and specifically, in addition to the polymer (X1), contains a pressure-sensitive adhesive, a cross-linking agent, and other additives to be blended as needed. To do. The pressure-sensitive adhesive composition may be diluted with a diluting solution such as an organic solvent. The diluting solution may be the solvent used when synthesizing the polymer (X1), or may be added after synthesizing the polymer (X1).
The pressure-sensitive adhesive composition may be crosslinked by heating and drying, if necessary, to become a pressure-sensitive adhesive. The adhesive is usually used for an adhesive tape or the like, and may form an adhesive layer.

<Adhesive tape>
The adhesive tape of the present invention is an adhesive tape provided with an adhesive layer made of the above-mentioned adhesive. The adhesive tape may be a non-support tape having no base material or an adhesive tape having a base material, but is preferably an adhesive tape having a base material. The adhesive tape may be referred to as an adhesive sheet as described later.
The non-support tape is a double-sided adhesive tape that is used in the state of a single layer of an adhesive layer without having a base material. The pressure-sensitive adhesive tape having a base material includes a base material and an adhesive layer provided on at least one surface of the base material. In this case, the adhesive tape may be used as a double-sided adhesive tape by providing adhesive layers on both sides of the base material, or may be used as a single-sided adhesive tape by providing an adhesive layer on only one side of the base material. May be good. In each adhesive tape, a release sheet may be appropriately attached to the surface of the exposed adhesive layer to protect it. The release sheet is formed by applying a release agent to at least one surface of the release sheet base material to form a release surface, and the release sheet may be attached so that the release surface is in contact with the pressure-sensitive adhesive layer.
In the double-sided adhesive tape having adhesive layers on both sides of the base material, at least one of the adhesive layers may be composed of the above-mentioned adhesive of the present invention.

[Base material]
The base material used for the adhesive tape is not particularly limited, but is preferably any of a resin film, a non-woven fabric, or a foam.
Specifically, the resin components constituting the resin film include polyethylene terephthalate (PET), polyethylene furanoate (PEF), polylactic acid (PLA), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and poly. Polyester (PES) such as butylene succinate (PBS), polyethylene (PE), polypropylene (PP), polyolefin such as ethylene vinyl acetate copolymer (EVA), polyurethane (PU), triacetyl cellulose (TAC), polyamide ( PA) and the like. These resin components may be used alone or in combination of two or more. Among the above, the resin film is preferably a polyethylene terephthalate film (PET film). The PET film has good mechanical strength and can properly support the pressure-sensitive adhesive layer. Further, as a PET film, a product having a high bio-rate is commercially available, and the bio-rate as an adhesive tape is likely to be high.

The non-woven fabric may be a non-woven fabric composed of a resin component, or may be a non-woven fabric using fibers other than the resin component such as pulp. The non-woven fabric using fibers other than the resin component may be formed of the fibers other than the resin component alone, or may be formed of both the fibers other than the resin component and the resin fibers. As the resin component, for example, those listed as the resin components constituting the above-mentioned resin film may be appropriately selected and used. Further, as a non-woven fabric using pulp, a product having a high bio-rate is commercially available, and it is easy to increase the bio-rate as an adhesive tape.
When a foam is used as a base material, examples of the foam include a polyolefin resin foam using a polyolefin resin such as PE, PP, and EVA as a resin component, and a polyurethane foam using a polyurethane resin.

As the resin component constituting the resin film, the non-woven fabric, and the foam, for example, a resin derived from petroleum, a resin derived from animals and plants, and a resin derived from both petroleum and animals and plants may be used. It is preferable to contain at least a resin derived from animals and plants in order to make it a base product. For example, when the base material is a PET film, PET derived from animals and plants may be used. When a polyolefin resin foam or the like is used as the base material, the polyolefin resin constituting the foam may be derived from animals and plants.

In each adhesive tape, the thickness of the base material is not particularly limited, but is preferably 1 to 2000 μm, for example. The suitable range of the thickness of the base material varies depending on the type of the base material used. For example, when the base material is a resin film or a non-woven fabric, it is preferably 1 to 100 μm, more preferably 5 to 50 μm. .. By setting the thickness of these base materials to 5 to 100 μm, it is possible to impart a certain mechanical strength to the adhesive tape without impairing the flexibility.
When the base material is a foam, the thickness of the base material is preferably 50 to 2000 μm. Within the above range, it is possible to exhibit high impact resistance and high flexibility to adhere and bond the adherends along the shape of the adherend.

In each pressure-sensitive adhesive tape, the thickness of the pressure-sensitive adhesive layer is not particularly limited, but may be, for example, about 5 to 200 μm, preferably 10 to 100 μm. When the thickness of the pressure-sensitive adhesive layer is within this range, the obtained pressure-sensitive adhesive tape can exhibit sufficient adhesive strength.
The total thickness of the adhesive tape (total thickness of the base material and the adhesive layer) is preferably 10 to 400 μm. When the total thickness of the adhesive tape is within this range, the obtained adhesive tape can exhibit sufficient adhesive strength.

(Cohesive force)
The adhesive tape of the present invention preferably has a deviation amount of 500 μm or less, more preferably 400 μm or less, further preferably 300 μm or less, and 250 μm or less as measured by a cohesive force test at 23 ° C. Is particularly preferable. Further, the pressure-sensitive adhesive of the present invention preferably has a deviation amount of 1200 μm or less, more preferably 1000 μm or less, and further preferably 800 μm or less at 80 ° C. measured by a cohesive force test. When the amount of deviation at 23 ° C. and 80 ° C. becomes small as described above, the cohesive force of the pressure-sensitive adhesive layer becomes large, and the holding power at normal temperature and high temperature is improved.
The amount of deviation is the amount of deviation that occurs when a predetermined load is applied in the shearing direction for 3 minutes, and a detailed measurement method will be described later.

Further, after applying the load in the shearing direction for 3 minutes as described above, the displacement amount (displacement amount after the load removal) when the load is removed and recovered with respect to the displacement amount (displacement amount before the load removal). The ratio of is defined as the displacement displacement recovery rate (%). The displacement displacement recovery rate (%) is preferably 50% or less, more preferably 40% or less, further preferably 30% or less, and preferably 5% or more. It is more preferably% or more, and further preferably 15% or more. When the recovery rate is within the above range, the followability to the adherend when the adhesive tape is crimped is improved, and the stickability and adhesive strength are improved.

The amount of deviation can be measured by a cohesive force test using a minute shear displacement displacement measuring test device (manufactured by Asahi Seiko Co., Ltd., shear creep measuring device, NST1) shown in FIG. Specifically, it is as follows.
First, the release sheet on one side of the double-sided adhesive tape to be tested was peeled off, and a corona-treated polyethylene terephthalate (PET) film was attached to the surface of one exposed adhesive layer of the double-sided adhesive tape. Then, it is cut into a width of 1 cm and a length of 12 cm to obtain a test piece 5. The temperature controller 4 of the device is set to 23 ° C. or 80 ° C., and is left to stand until it stabilizes at the set temperature. The temperature controller 4 may be a combination of two or more temperature controllers as appropriate.
The other release sheet of the test piece 5 is peeled off from its end by about 3 cm to remove it, and the exposed adhesive layer is attached to the adherend 3 so that the adhesive area is 5 mm × 20 mm. At this time, the release sheet 8 remains attached to the pressure-sensitive adhesive layer 7 at a portion other than the end portion. The surface of the other exposed adhesive layer 7 of the test piece 5 is attached to the adherend 3 so that the adhesive area is 5 mm × 20 mm. The adherend 3 is made of SUS.
A quartz block 2 (chromium-deposited on quartz glass) whose end face is mirror-treated is placed on the sticking surface. The mirror-processed surface 10 of the end surface of the block 2 is irradiated with laser light from a laser interferometer 1 (for example, "SI-F1" manufactured by KEYENCE).
The test piece 5 is attached to a wire connecting to a 200 g weight 6, and left in that state to keep the temperature constant for 5 minutes. After 5 minutes, the load of the weight 6 is applied to the test piece 5 to apply a horizontal shear load to the test piece 5. Three minutes after the load is applied, the displacement of the block 2 on the test piece 5 is detected by the laser interferometer 1, and the detected value is used as the displacement amount of the adhesive.

In addition, the load is applied as described above, the load is removed after 3 minutes have passed, and the amount of displacement (after load removal) after 3 minutes has passed after the load has been removed is measured, and measured before the load is removed as described above. The amount of deviation is defined as the amount of deviation (before load removal), and the amount of deviation (after removal of load) / amount of deviation (before removal of load) × 100 (%) is defined as the displacement recovery rate (%). The amount of deviation (after the load is removed) is measured by the laser interferometer 1 in the same manner as the amount of deviation (before the load is removed). The specific calculation method of the displacement displacement recovery rate (%) is as follows.
Displacement recovery rate (%) = (displacement displacement (μm) 3 minutes after load removal) / (displacement displacement (μm) 3 minutes after load loading) × 100
Although the above description shows a method for measuring the amount of deviation in the double-sided adhesive tape, the same method may be used for the single-sided adhesive tape except that the PET film is not attached to the surface of one of the adhesive layers. Further, the double-sided adhesive tape can be similarly measured even with a non-support tape having no base material. Further, when the release sheet is not attached to the adhesive layer, the double-sided adhesive tape may be used in the same manner by omitting the peeling step and the like.

(Bio-rate of adhesive tape)
From the same viewpoint as the above-mentioned pressure-sensitive adhesive, the pressure-sensitive adhesive tape of the present invention preferably has a bio% of 40% by mass or more, more preferably 50% by mass or more, and further preferably 60% by mass or more. Further, the higher the bio-rate, the better, and it may be 100% by mass or less. The adhesive tape generally has a different biorate depending on each component (for example, the adhesive layer and the base material). Therefore, the bio-ratio may be calculated by obtaining the bio-ratio of each constituent member and weighting the mass of each constituent member by a weighted average.

(Manufacturing method of adhesive tape)
The method for producing the adhesive tape is not particularly limited, and the adhesive tape can be produced by a conventionally known production method. For example, first, if necessary, a pressure-sensitive adhesive composition diluted with an organic solvent or the like is prepared, the pressure-sensitive adhesive composition is applied onto a support such as a release sheet, and if necessary, it is heated and dried. , The pressure-sensitive adhesive layer may be formed. When the pressure-sensitive adhesive composition is applied to the release sheet, it may be applied on the release surface of the release sheet. The pressure-sensitive adhesive layer formed on the support such as a release sheet is further attached to the base material to obtain an adhesive tape having the base material. Alternatively, the pressure-sensitive adhesive composition may be directly applied to the base material, heated and dried as needed to obtain a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on the base material.
When producing a double-sided adhesive tape, an adhesive layer may be formed on both sides of the base material by any of the above methods.
Further, in the case of producing a non-support tape, the pressure-sensitive adhesive composition can be applied to a release sheet, and if necessary, heated and dried to form a pressure-sensitive adhesive layer. In this case, a release sheet may be further attached to the formed pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer. For non-support tapes, the pressure-sensitive adhesive layer may be peeled off from the release sheet before use.

(Use of adhesive)
The use of the pressure-sensitive adhesive and the pressure-sensitive adhesive tape of the present invention is not particularly limited, but it is preferably used in electric appliances and vehicle applications. For example, in electric appliances, it is preferable that they are used for fixing the parts constituting the electric appliances. Specifically, in electrical appliances, it is preferable to fix the parts to each other with an adhesive or an adhesive tape. Therefore, the present invention also provides an electric appliance provided with the above-mentioned pressure-sensitive adhesive or pressure-sensitive adhesive tape. The electrical appliances are not particularly limited, and examples thereof include portable electronic devices, various displays such as televisions, washing machines, refrigerators, dishwashers, vacuum cleaners, printers, and various audio devices.

Further, in vehicle applications, for example, it is preferable to use it for fixing in-vehicle members. Examples of in-vehicle members include in-vehicle panels such as ceiling panels, door panels, and instrument panels, car air conditioners, door trims, vibration damping members, emblems, decorative films, and water blocking members. Be done. The in-vehicle member may be fixed to the vehicle via, for example, an adhesive or an adhesive tape. Therefore, the present invention also provides an in-vehicle member provided with the above-mentioned pressure-sensitive adhesive or pressure-sensitive adhesive tape.

Electric appliances and the inside of vehicles may be exposed to high temperatures, but the adhesive of the present invention exerts high holding power even in a high temperature environment, so it is possible to stably fix parts of electric appliances and in-vehicle members. it can. On the other hand, assembling of electric appliances and vehicles may be performed in a cold region, and even if it is performed in a cold region, an adhesive or an adhesive tape can be easily attached to an electric appliance part or an in-vehicle member. Therefore, the assembleability is good. Further, parts of electrical appliances, in-vehicle members, etc. may be composed of polyolefin resins typified by polypropylene resin and have low polarity, but even if these are low polarity, the adhesive of the present invention or If an adhesive tape is used, it can be attached with high adhesive strength.

<< Second Invention >>
Hereinafter, the second invention of the present invention will be described in detail using embodiments.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention includes a pressure-sensitive adhesive containing a plant-derived component. For example, as will be described later, the polymer (X2) contained in the pressure-sensitive adhesive may contain a plant-derived monomer component as a constituent unit. In addition, components other than the polymer (X2) such as the tackifier may also contain plant-derived components. Without a pressure-sensitive adhesive containing plant-derived components, it is difficult to increase the bio-rate of the pressure-sensitive adhesive sheet.

(Adhesive)
The peak top molecular weight (Mtp) of the sol content of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention is 137,000 or more and 300,000 or less, and the sol content (R _sol ) of the pressure-sensitive adhesive is 90% by mass or less. The glass transition temperature (Tg) of the pressure-sensitive adhesive is 5 ° C. or lower. As a result, it is possible to improve both the holding power at a high temperature and the adhesiveness to a low-polarity adherend while increasing the bio-rate of the pressure-sensitive adhesive sheet and improving the low-temperature adhesiveness.

<Peak top molecular weight of sol (Mtp)>
The peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention by GPC is 137,000 or more and 300,000 or less. If the peak top molecular weight is less than 137,000, the holding power at high temperature and the adhesiveness to a low-polarity adherend may be deteriorated. Further, if the peak top molecular weight is larger than 300,000, the adhesiveness to a low-polarity adherend may be deteriorated. From such a viewpoint, the peak top molecular weight is preferably 138,000 or more and 220,000 or less, and more preferably 138,000 or more and 200,000 or less. The peak top molecular weight of the sol of the pressure-sensitive adhesive by GPC is the value of the molecular weight that becomes the peak top in the molecular weight distribution obtained by GPC measurement, and can be measured by the method described in Examples described later. The peak top molecular weight (Mtp) of the sol component by GPC is the peak top molecular weight of the sol component of the main component polymer by GPC, and does not include the peak derived from the tackifier (TF).
The peak top molecular weight of the sol of the pressure-sensitive adhesive by GPC can be adjusted by changing the molecular weight and molecular weight distribution of the polymer constituting the pressure-sensitive adhesive, changing the blending amount of the cross-linking agent, or blending a low molecular weight component such as an oligomer. It can be adjusted by doing.

<Sol fraction (R _sol )>
_{The sol fraction (R sol} ) of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention is 90% by mass or less. If the sol fraction (R _sol ) of the pressure-sensitive adhesive is higher than 90% by mass, the holding power at high temperature may be deteriorated. _{The sol fraction (R sol} ) of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention is preferably 45% by mass or more and 75% by mass or less. When the sol fraction (R _sol ) is 45% by mass or more, the adhesiveness to a low-polarity adherend can be further improved while increasing the bio-ratio. Further, when the sol fraction (R _sol ) is 75% by mass or less, the holding power at high temperature can be further improved while increasing the bio-ratio. From such a viewpoint, the sol fraction (R _sol ) is more preferably 50% by mass or more and 70% by mass or less, still more preferably 55% by mass or more and 70% by mass or less, and even more preferably 58% by mass. % Or more and 70% by mass or less. The sol fraction (R _sol ) can be measured by the method described in Examples described later. The sol fraction (R _sol ) is determined by changing the molecular weight and molecular weight distribution of the polymer constituting the pressure-sensitive adhesive by the polymerization method, changing the blending amount of the cross-linking agent, or blending a low molecular weight component such as an oligomer. Can be adjusted by.

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention is 5 ° C. or lower. If the glass transition temperature (Tg) is higher than 5 ° C., the low-temperature stickability may deteriorate. From such a viewpoint, the glass transition temperature (Tg) is preferably 2.5 ° C. or lower, more preferably 0 ° C. or lower, and further preferably -1 ° C. or lower. The upper limit of the glass transition temperature (Tg) range is not particularly limited, but is preferably −20 ° C. or higher, more preferably −18 ° C. or higher, and further, from the viewpoint of improving the holding power at high temperatures. It is preferably -17 ° C or higher. The glass transition temperature (Tg) can be measured by the method described in Examples described later. The glass transition temperature (Tg) can be adjusted by the type and amount of the monomers constituting the polymer of the pressure-sensitive adhesive. Further, the type and amount of the tackifier can be adjusted. For example, by using a tackifier having a high softening point or increasing the amount of the tackifier, the glass transition temperature (Tg) can be adjusted. Is likely to be high. The glass transition temperature (Tg) can also be adjusted by adding fine particles or the like.

<Hardness and softness (S)>
The hardness (S) represented by the following general formula (3) in the pressure-sensitive adhesive of the pressure-sensitive adhesive sheet of the present invention is preferably 50,000 or more and 180,000 or less. Hardness and softness (S) is a parameter representing the softness of the pressure-sensitive adhesive. When the hardness (S) is within a predetermined range, the pressure-sensitive adhesive exhibits excellent adhesive performance without being too soft or too hard.
S = Mw × R _sol / D (3)
In the formula (3), Mw represents the weight average molecular weight of the sol of the pressure-sensitive adhesive by GPC, R _sol represents the sol content of the pressure-sensitive adhesive, and D represents the dispersity of the sol of the pressure-sensitive adhesive by GPC. Represent.
When the hardness and softness (S) is 50,000 or more, the holding power at high temperature and the adhesiveness to a low-polarity adherend can be further improved while increasing the biorate. Further, when the hardness and softness (S) is 180,000 or less, the holding power under high temperature can be further improved while increasing the biorate. From such a viewpoint, the hardness and softness (S) is more preferably 55,000 or more and 120,000 or less, and further preferably 60,000 or more and 112,000 or less. The hardness and softness (S) can be measured by the method described in Examples described later. Further, the hardness and softness (S) are adjusted by changing the molecular weight and molecular weight distribution of the polymer constituting the pressure-sensitive adhesive by the polymerization method, changing the blending amount of the cross-linking agent, and blending a low molecular weight component such as an oligomer. can do.

<Dispersity (D)>
The dispersity (D) of the sol component in the pressure-sensitive adhesive of the pressure-sensitive adhesive sheet of the present invention by GPC is preferably 1.6 or more and less than 3. When the dispersity (D) is 1.6 or more, it is possible to further improve the adhesiveness to the low-polarity adherend while increasing the biorate. Further, when the dispersity (D) is less than 3, the holding power at high temperature can be further improved while increasing the biorate. From this point of view, the dispersity (D) is more preferably 1.8 or more and less than 3, still more preferably 1.9 or more and less than 3, and even more preferably 2.0 or more and less than 3. The degree of dispersion (D) can be measured by the method described in Examples described later. Further, the dispersity (D) of the sol component by GPC is the dispersity of the sol component of the polymer as the main component by GPC, and does not include the molecular weight due to the peak derived from the tackifier (TF).
The dispersity (D) can be adjusted by changing the molecular weight of the polymer constituting the pressure-sensitive adhesive, changing the blending amount of the cross-linking agent, or blending a low molecular weight component such as an oligomer by a polymerization method.

<Weight average molecular weight (Mw)>
The weight average molecular weight (Mw) of the sol of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention by GPC is preferably 190000 or more and 700,000 or less. When the weight average molecular weight (Mw) is 190,000 or more and 700,000 or less, it is possible to further improve the holding power at high temperature and the adhesiveness to a low-polarity adherend while increasing the biorate. From such a viewpoint, the weight average molecular weight (Mw) is more preferably 200,000 or more and 600,000 or less, further preferably 220,000 or more and 550000 or less, and even more preferably 240000 or more and 460000 or less. The weight average molecular weight (Mw) can be measured by the method described in Examples described later. Further, the weight average molecular weight (Mw) of the sol component by GPC is the weight average molecular weight of the sol component of the polymer as the main component by GPC, and does not include the molecular weight due to the peak derived from the tackifier (TF).
The weight average molecular weight (Mw) is adjusted by changing the molecular weight and molecular weight distribution of the polymer constituting the pressure-sensitive adhesive by the polymerization method, changing the blending amount of the cross-linking agent, or blending a low molecular weight component such as an oligomer. be able to.

<Bio rate>
The pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention preferably has a carbon content of biological origin (hereinafter, also referred to as "bio-rate") of 51% by mass or more. By setting the bio ratio to 51% by mass or more, the pressure-sensitive adhesive can be made into a "bio-based product". Bio-based products can save petroleum resources by using renewable organic resources, reduce carbon dioxide emissions from combustion of petroleum-derived products, and reduce the burden on the environment. From these viewpoints, the biorate is more preferably 55% by mass or more, and further preferably 60% by mass or more. Further, the higher the bio-rate, the better, and it may be 100% by mass or less. Since the method for measuring the biorate has been described in the item of the first invention, it will be omitted.

<Polymer (X2)>
The pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention preferably contains a polymer (X2). The polymer (X2) is at least one monomer (Y2) selected from the group consisting of the monomer (A2) represented by the following general formula (4) and the monomer (B2) represented by the following general formula (5). ) Derived from the constituent units. In addition, in this specification, the term "monomer (Y2)" is also used to collectively explain a monomer (A2) and a monomer (B2).

In formula (4), R ⁴ represents H or CH ₃ , R ⁵ represents −C _n H _{2n + 1} , and n represents an integer of 7 to 20. In equation (5), R ⁶ represents −C (= O) C _m H _{2m + 1} , and m represents an integer of 6 to 13. The monomer (A2) represented by the general formula (4) is different from the monomer (A1) represented by the general formula (1) in that n represents an integer of 7 to 20, and the general formula (5) is used. The monomer (B2) represented by is the same as the monomer (B1) represented by the general formula (2).

In the present invention, by containing at least one of the monomer (A2) and the structural unit derived from the monomer (B2), the holding power at a high temperature, the low temperature stickability, and the adhesiveness to a low-polarity adherend can be obtained. It becomes easier to improve. In addition, the monomer (A2) and the monomer (B2) can be easily produced from biological raw materials, and the biorate, which will be described later, can be easily increased.

The polymer (X2) may contain a structural unit derived from one or both of the monomer (A2) and the monomer (B2), but preferably contains a structural unit derived from the monomer (A2). When the polymer (X2) has a structural unit derived from the monomer (A2), it is easy to improve the holding power at high temperature, the low temperature stickability, and the adhesiveness to a low-polarity adherend.

The alkyl group ^{of R 5} in the formula (4) _{(-C n} H _{2n + 1} ) and the alkyl group ^{of R 6} in the formula (4) _{(-C m} H _{2m + 1} ) may be linear or branched. However, the linear shape is preferable from the viewpoint of holding power at high temperature, low temperature stickability, and adhesiveness to a low-polarity adherend. Also, the holding power at high temperatures, low temperature bondability, and from the viewpoint of easily improving the adhesion to low polarity adherends, n represents 7 to 18 preferably in R ^5, and more preferably from 7 to 14, 7 Is even more preferable. Further, from the viewpoint of improving the adhesive performance, it is preferable that ^{R 4 is H in the formula (4).}
Thus, the polymer (X2) is, in general formula (4) n is 7-18 in, and it is preferable ^{that R 5} contains a constitutional unit derived from monomer (A2) is a straight-chain, with n is 7, Moreover, it is more preferable to contain a structural unit derived from the monomer (A2) in which R ⁵ is linear, and it is further preferable that ^{R 4 is H in the monomer (A2) in this case.}

Specific examples of the monomer (A2) include n-heptyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, n-decyl (meth) acrylate, and 2-octyl (meth). Examples thereof include acrylate, n-nonyl (meth) acrylate, n-undecyl (meth) acrylate, n-tetradecyl (meth) acrylate (myristyl (meth) acrylate), and n-octadecyl (meth) acrylate. These monomers (A2) may be used alone or in combination of two or more.
Specific examples of the monomer (B2) include vinyl caprate, vinyl laurate, vinyl caprylate, vinyl nonanoate and the like. These monomers (B2) may be used alone or in combination of two or more.
Among the above-mentioned monomers (A2) and (B2), n-heptyl (meth) acrylate, n-tetradecyl (meth) acrylate and n-octadecyl (meth) acrylate are preferable, and n-heptyl (meth) acrylate is more preferable. Preferably, n-heptyl acrylate is even more preferred. The use of n-heptyl (meth) acrylates, n-tetradecyl (meth) acrylates and n-octadecyl (meth) acrylates improves retention at high temperatures, low-temperature stickability, and adhesion to low-polarity adherends. It will be easier to make it.
In addition, in this specification, (meth) acrylate is used as a term meaning one or both of acrylate and methacrylate, and other similar terms are also used.

Further, in the above general formulas (4) and (5), ^{it is preferable that R 5} and R ⁶ are carbons derived from living organisms, particularly plants. By using ^{carbon of biological origin for R 5} and R ⁶ , the biorate described later can be increased. Monomers (A2) and (B2), each of which is a biological carbon in R ⁵ and R ^6, are obtained by using saturated fatty acids or unsaturated fatty acids collected from animals and plants as raw materials and alcoholizing and esterifying them. It is inexpensive and easily available.

In the present invention, the content of the structural unit derived from the monomer (Y2) (that is, at least one monomer selected from the monomer (A2) and the monomer (B2)) is 48% by mass or more in the polymer (X2). Is preferable. When this content is 48% by mass or more, it is easy to improve the holding power at high temperature, the low temperature stickability, and the adhesiveness to a low-polarity adherend while increasing the biorate. Become.
From the viewpoint of improving the various performances described above while increasing the biorate, the content of the structural unit derived from the monomer (Y2) is more preferably 70% by mass or more, further preferably 80% by mass or more, and 90% by mass. The above is even more preferable. The content of the structural unit derived from the monomer (Y2) is preferably 99% by mass or less, more preferably 98% by mass or less, and 97.5% by mass, for example, in order to contain a predetermined amount of the functional group-containing monomer described later. The following is more preferable.

Further, as described above, the monomer (A2) is at least one (meth) acrylate selected from the group consisting of n-heptyl (meth) acrylate, n-tetradecyl (meth) acrylate and n-octadecyl (meth) acrylate. Is preferably included. The content of the structural units derived from these (meth) acrylates in the polymer (X2) is preferably 48% by mass or more, more preferably 70% by mass or more, from the viewpoint of improving the above-mentioned various performances while increasing the biorate. 80% by mass or more is more preferable, and 90% by mass or more is particularly preferable. The content of the structural units derived from these (meth) acrylates is preferably 99% by mass or less, more preferably 98% by mass or less, and further preferably 97.5% by mass or less.

Further, the monomer (A2) preferably contains n-heptyl (meth) acrylate, and is n as the main monomer from the viewpoint of tan δ (23 ° C.) and from the viewpoint of improving the above-mentioned various performances while increasing the biorate. -It is more preferable to contain heptyl (meth) acrylate. Specifically, the content of the structural unit derived from n-heptyl (meth) acrylate in the polymer (X2) is preferably 48% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and 90% by mass or more. Mass% or more is particularly preferable. The content of the structural unit derived from n-heptyl (meth) acrylate is preferably 99% by mass or less, more preferably 98% by mass or less, and further preferably 97.5% by mass or less. The n-heptyl (meth) acrylate is preferably n-heptyl acrylate.

The polymer (X2) preferably contains a structural unit derived from another monomer other than the above-mentioned monomer (A2) and monomer (B2). The other monomer is preferably a monomer having a polymerizable carbon-carbon double bond such as a vinyl group and a (meth) acryloyl group. As the other monomer, a monomer containing a polar group (hereinafter, also referred to as “polar group-containing monomer (C)”) is preferable. Since the polymer (X2) contains a structural unit derived from the polar group-containing monomer (C), it becomes easy to increase the adhesive strength of the pressure-sensitive adhesive, which provides holding power at high temperature, low-temperature stickability, and low-polarity adherend. It becomes easy to improve the adhesiveness to the surface.
The polar group is a functional group having an active hydrogen, and specific examples thereof include a carboxy group, a hydroxyl group, an amino group, and an amide group. The polar group may be a functional group capable of reacting with a cross-linking agent described later. The polar group-containing monomer (C) may be used alone or in combination of two or more. Since the polar group-containing monomer (C) is the same as that described in the item of the first invention, the description thereof will be omitted.

The weight average molecular weight (Mw) of the polymer (X2) is preferably 200,000 or more and 1.1 million or less. When the weight average molecular weight (Mw) is 200,000 or more, the shear strength of the pressure-sensitive adhesive can be increased and the holding power of the pressure-sensitive adhesive under high temperature can be increased. Further, when it is 1.1 million or less, the adhesive strength of the pressure-sensitive adhesive is improved, and it becomes easy to improve the low-temperature adhesiveness and the adhesiveness to a low-polarity adherend.
From these viewpoints, the weight average molecular weight (Mw) is more preferably 300,000 or more, further preferably 400,000 or more, still more preferably 1.05 million or less, still more preferably 1 million or less.
The weight average molecular weight (Mw) can be appropriately adjusted by appropriately selecting the amount of the polymerization initiator used, the polymerization conditions such as the polymerization temperature, the polymerization method, and the like.
The weight average molecular weight is a standard polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

The polymer (X2) is the main component of the adhesive. The content of the polymer (X2) in the pressure-sensitive adhesive is, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 65% by mass or more in order to impart appropriate adhesive performance. Further, the polymer (X2) in the pressure-sensitive adhesive is preferably 99% by mass or less, and further 95% by mass or less so that a predetermined amount of components other than the polymer (X2) such as a tackifier and a cross-linking agent can be blended in the pressure-sensitive adhesive. It is preferable, and more preferably 92% by mass or less.

Since the low molecular weight component of the polymer (X2) is the sol component, the above characteristics of the sol component of the pressure-sensitive adhesive can be adjusted by changing the molecular weight and molecular weight distribution of the polymer (X2) by the polymerization method. Further, by changing the blending amount of the cross-linking agent, the low molecular weight component of the polymer (X2) remains in the pressure-sensitive adhesive without cross-linking. Can be adjusted. Examples of the low molecular weight component of the polymer (X2) include oligomers derived from monomers that are raw materials for the polymer (X2).

<Manufacturing method of polymer (X2)>
The polymer (X2) can be obtained by radically reacting a mixture of the above-mentioned raw material monomers in the presence of a polymerization initiator. As a result, the molecular weight distribution of the polymer (X2) can be considerably widened, and the sol fraction can be increased.
The radical reaction method is not particularly limited, and examples thereof include free radical polymerization and living radical polymerization. According to the free radical polymerization, the molecular weight distribution can be widened as compared with the living radical polymerization, whereby the amount of low molecular weight components produced can be increased. As a result, the sol content of the pressure-sensitive adhesive can be further increased, and while the biorate is increased, the holding power at high temperature, the low-temperature stickability, and the adhesiveness to a low-polarity adherend are further improved. Can be done. The polymerization method is not particularly limited, and conventionally known methods can be used. Examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization and the like. Of these, solution polymerization is preferable because it is easy to synthesize. Since the method for producing the polymer (X2) is the same as the method for producing the polymer (X1) described in the item of the first invention, the description thereof will be omitted.

In the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention, a low molecular weight component (Z) may be added to the polymer obtained by the above-mentioned production method to obtain a polymer (X2). As described above, by changing the molecular weight and molecular weight distribution of the polymer (X2) by the polymerization method, the above-mentioned characteristics of the sol content of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention can be adjusted within the above-mentioned range. However, even if the low molecular weight component (Z) is used, the above-mentioned characteristics of the sol content of the pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention can be adjusted so as to fall within the above-mentioned range. The low molecular weight component (Z) also has a function as a tackifier.
The low molecular weight component (Z) is preferably an oligomer of a monomer that is a raw material of the polymer (X2). Therefore, the low molecular weight component (Z) is selected from at least a group consisting of the monomer (A2) represented by the above-mentioned general formula (4) and the monomer (B2) represented by the above-mentioned general formula (5). It is preferably an oligomer containing a structural unit derived from one type of monomer (Y2). Since the monomer used for the low molecular weight component (Z) has already been described in the item of the polymer (X2) described above, the description of the monomer used for the low molecular weight component (Z) will be omitted.

Similar to the polymer (X2), among the above-mentioned monomers (A2) and (B2), n-heptyl (meth) acrylate, tetradecyl (meth) acrylate and octadecyl (meth) acrylate are preferable, and n-heptyl (meth) acrylate is preferable. ) Acrylate is more preferable, and n-heptyl acrylate is further preferable. Therefore, as the low molecular weight component (Z), n-heptyl (meth) acrylate oligomer, tetradecyl (meth) acrylate oligomer and octadecyl (meth) acrylate oligomer are preferable, and n-heptyl (meth) acrylate oligomer is more preferable, and n-. Heptyl acrylate oligomers are even more preferred.
The content of the low molecular weight component (Z) in the polymer (X2) is not particularly limited, and may be appropriately adjusted so that various properties of the gel fraction are within the above range.

<Adhesive imparting agent>
The pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention preferably contains a pressure-sensitive adhesive in addition to the polymer (X2). The tackifier added to the polymer (X2) is the same as the tackifier added to the polymer (X1) described in the item of the first invention, except for the content as described below, and thus the description thereof is omitted. To do.

When the pressure-sensitive adhesive contains a pressure-sensitive adhesive, the content of the pressure-sensitive adhesive is not particularly limited, but is preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymer (X2). When the content of the tackifier is at least the above lower limit value, it becomes easy to improve the low-temperature adhesiveness and the adhesiveness to a low-polarity adherend. Further, by setting it to the above upper limit value or less, it is possible to prevent the holding power from being lowered at a high temperature. From the above viewpoint, in the second invention, the content of the tackifier is more preferably 12 parts by mass or more and 40 parts by mass or less, and further preferably 14 parts by mass or more and 30 parts by mass or less.

<Crosslinking agent>
The pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention preferably contains a cross-linking agent and is cross-linked. That is, the pressure-sensitive adhesive is preferably one obtained by cross-linking a pressure-sensitive adhesive composition containing a cross-linking agent in addition to the above-mentioned polymer (X2) or polymer (X2) and a pressure-sensitive adhesive. The cross-linking agent added to the polymer (X2) is the same as the cross-linking agent added to the polymer (X1) described in the item of the first invention, except for the blending amount as described below, and thus the description thereof will be omitted.

The blending amount of the cross-linking agent in the pressure-sensitive adhesive may be appropriately changed according to the type of the polymer (X2), desired physical properties such as the degree of cross-linking, etc., but in the second invention, with respect to 100 parts by mass of the polymer (X2). For example, it is 0.1 parts by mass or more and 20 parts by mass or less, preferably 0.5 parts by mass or more and 8 parts by mass or less, and more preferably 0.6 parts by mass or more and 4 parts by mass or less.

<Other additives>
The pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention contains, if necessary, additives such as a silane coupling agent, an antioxidant, an ultraviolet inhibitor, a plasticizer, an emulsifier, a softening agent, a filler, a pigment, and a dye. May be. As these additives, it is preferable to select a biological material as much as possible from the viewpoint of increasing the biorate.

<Making adhesive>
The pressure-sensitive adhesive in the pressure-sensitive adhesive sheet of the present invention may be formed from, for example, a pressure-sensitive adhesive composition prepared. The pressure-sensitive adhesive composition comprises components for forming a pressure-sensitive adhesive. The pressure-sensitive adhesive composition preferably contains the above-mentioned polymer (X2). The pressure-sensitive adhesive composition may further contain a pressure-imparting agent, a cross-linking agent, other additives, and the like, if necessary. The pressure-sensitive adhesive composition may be diluted with a diluting solution such as an organic solvent. The diluting solution may be the solvent used when synthesizing the polymer (X2), or may be added after synthesizing the polymer (X2).
The pressure-sensitive adhesive composition may be crosslinked by heating and drying, if necessary, to become a pressure-sensitive adhesive. The pressure-sensitive adhesive is used for the pressure-sensitive adhesive sheet of the present invention. By appropriately setting the heating temperature at the time of cross-linking, the peak top molecular weight of the sol can be appropriately adjusted.
The heating temperature at the time of crosslinking is not particularly limited, but is, for example, 90 ° C. or higher and 130 ° C. or lower, preferably 100 ° C. or higher and 120 ° C. or lower. The heating time is, for example, 30 seconds or more and 10 minutes or less, preferably 1 minute or more and 5 minutes or less. Further, in order to further proceed the cross-linking reaction, it is preferable to cure the pressure-sensitive adhesive after drying it. The curing temperature is preferably 20 ° C. or higher and 60 ° C. or lower, and more preferably 30 ° C. or higher and 50 ° C. or lower. The curing time is preferably 1 day or more and 10 days or less, and more preferably 2 days or more and 5 days or less.

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention is provided with the above-mentioned pressure-sensitive adhesive, and specifically, is provided with a pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive. The pressure-sensitive adhesive sheet may be a pressure-sensitive adhesive sheet having no base material or a pressure-sensitive adhesive sheet having a base material, but a pressure-sensitive adhesive sheet having a base material is preferable.
The pressure-sensitive adhesive sheet having no base material is, for example, a non-support tape. The non-support tape is a double-sided adhesive tape that is used in the state of a single layer of an adhesive layer without having a base material. The pressure-sensitive adhesive sheet having a base material is, for example, an pressure-sensitive adhesive tape. The adhesive tape comprises a substrate and an adhesive layer provided on at least one surface of the substrate. In this case, the adhesive tape may be a double-sided adhesive tape in which adhesive layers are provided on both sides of the base material, or may be a single-sided adhesive tape in which the adhesive layer is provided on only one side of the base material. ..
In the double-sided adhesive tape having adhesive layers on both sides of the base material, at least one adhesive layer may be composed of the above-mentioned adhesive.

In the adhesive sheet, a release sheet may be appropriately attached to the surface of the exposed adhesive layer to protect it. The release sheet is formed by applying a release agent to at least one surface of the release sheet base material to form a release surface, and the release sheet may be attached so that the release surface is in contact with the pressure-sensitive adhesive layer.

[Base material]
The base material used for the pressure-sensitive adhesive sheet is not particularly limited, but is preferably any of a resin film, a non-woven fabric, or a foam. Since the base material used for the pressure-sensitive adhesive sheet is the same as the base material for the pressure-sensitive adhesive tape described in the item of the first invention, the description thereof will be omitted.

In the pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive layer is not particularly limited, but may be, for example, about 5 μm or more and 200 μm or less, preferably 10 μm or more and 100 μm or less. When the thickness of the pressure-sensitive adhesive layer is within this range, the obtained pressure-sensitive adhesive sheet can exhibit sufficient adhesive strength.
The total thickness of the pressure-sensitive adhesive sheet (total thickness of the base material and the pressure-sensitive adhesive layer) is preferably 10 μm or more and 2200 μm or less. When the total thickness of the pressure-sensitive adhesive sheet is within this range, the obtained pressure-sensitive adhesive sheet can exhibit sufficient adhesive strength.

(Tack value)
The pressure-sensitive adhesive for the pressure-sensitive adhesive sheet of the present invention preferably has a peeling limit value of 90 gf · s or more at 23 ° C. as measured by a tack test. The tack test is performed as follows.
First, an adhesive layer with a thickness of 50 μm is applied to a PET substrate having a thickness of 23 μm on a plate set to 23 ° C. of a tack tester (for example, TAC-1000 manufactured by Reska) so that the adhesive layer is on top. And put the adhesive tape on it. Fix the tape from above with the sample holder attached to the tack tester. Next, a cylindrical stainless steel probe having a diameter of 5 mm is pressed against the adhesive tape at a probe temperature of 23 ° C., a pressing speed of 5 mm / s, and a pressing load of 100 gf, and is held in that state for 10 seconds. After that, the probe is pulled up at a pulling speed of 5 mm / s. The force applied to the adhesive tape during this period is measured.
In the above description, an example in which the adhesive constitutes the adhesive tape has been described, but even when the adhesive does not form the adhesive, the adhesive is similarly placed on the plate set at 23 ° C. of the tack tester. It is good to measure in the same way.

The peeling limit value is an integral value from the time T1 at which the force indicates 0 to the time indicating the maximum force (peak top) in the force-time curve indicating the force applied to the adhesive tape at 23 ° C. measured by the tack test. Means. In the tack test, when the probe is pressed against the adhesive tape, the force-time curve goes down, and then when the probe is started to be pulled up, the force-time curve goes up. The integrated value from the time T1 at which the force indicates 0 to the time T2 at which the maximum force (peak top) is indicated is calculated, and this is set as the peeling limit value.
By adjusting the peeling limit value to the above range, peeling of the adhesive tape can be suppressed even under a high temperature and high humidity condition and a situation where a restoring force is applied. The preferable lower limit of the peeling limit value is 100 gf · s, and the more preferable lower limit is 110 gf · s. Further, the upper limit of the peeling limit value is not particularly limited.

<Bio rate>
From the same viewpoint as the above-mentioned pressure-sensitive adhesive, the pressure-sensitive adhesive sheet of the present invention preferably has a bio% of 40% by mass or more, more preferably 50% by mass or more, and further preferably 60% by mass or more. Further, the higher the bio-rate, the better, and it may be 100% by mass or less. The pressure-sensitive adhesive sheet generally has a different biorate depending on each component (for example, the pressure-sensitive adhesive layer and the base material). Therefore, the bio-ratio may be calculated by obtaining the bio-ratio of each constituent member and weighting the mass of each constituent member by a weighted average.

(Manufacturing method of adhesive sheet)
The method for producing the pressure-sensitive adhesive sheet is not particularly limited, and the pressure-sensitive adhesive sheet can be produced by a conventionally known production method. Since the method for manufacturing the adhesive sheet is the same as the method for manufacturing the adhesive tape described in the item of the first invention, the description thereof will be omitted.

(Use of adhesive sheet)
The use of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but it is preferably used in electric appliances and vehicle applications. Since the method for producing the adhesive sheet is the same as the use of the adhesive and the adhesive tape described in the item of the first invention, the description thereof will be omitted.

The present invention may be a combination of the first invention and the second invention.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to the scope of the Examples.

<< First Example >>
[Measurement and evaluation method]
The measurement and evaluation of each physical property were carried out as follows.
<Elastic modulus>
The storage elastic modulus G', the loss elastic modulus G', and the glass transition temperature (Tg) at each temperature are measured by the polymer dynamic viscoelasticity measuring device "itkDVA-200" (manufactured by IT Measurement Control Co., Ltd.) under the following conditions. did.
Measurement mode: Shear temperature rise rate: 5 ° C / min Measurement temperature range: -30 to 150 ° C
Setting distortion: 0.1%
Frequency: 10Hz
As the measurement sample, in the present example and the comparative example, the pressure-sensitive adhesive composition solution prepared in each example is molded so that the finally obtained sample shape has a thickness of 0.1 mm, a width of 0.6 mm, and a length of 10 mm. Then, it was prepared by heating and drying under the same conditions as when the pressure-sensitive adhesive layer was formed in each example.

<Weight average molecular weight>
The weight average molecular weight (Mw) of the polymer (X1) was measured by a GPC apparatus "HLC822GPC" (manufactured by Tosoh Corporation) and determined by polystyrene conversion. Specifically, the obtained polymer (X1) is diluted 50-fold with tetrahydrofuran (THF), and the obtained diluent is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm) and measured. Samples were prepared. This measurement sample was supplied to a gel permeation chromatograph (2690 Separations Model manufactured by Waters), GPC measurement was performed under the conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C., and the polymer (X1) was converted into polystyrene. The molecular weight was measured to determine the weight average molecular weight.

<Crosslink degree>
The pressure-sensitive adhesive (sample) was collected in W1 (g), and the insoluble matter when the collected sample was immersed in ethyl acetate at 23 ° C. for 24 hours was filtered through a 200-mesh wire mesh. The residue on the wire mesh was dried under the condition of 110 ° C. for 1 hour, the mass W2 (g) after drying was measured, and the gel fraction (crosslinking degree) was calculated by the following formula.
Gel fraction (mass%) = 100 x W2 / W1
<Bio rate>
The biorate of the adhesive was measured according to ASTM 6866.

<Low temperature stickability>
One side of the double-sided adhesive tape cut to a width of 25 mm and a length of 100 mm according to JIS Z-1528 "Double-sided adhesive tape" is a polypropylene plate (manufactured by Takiron) with a thickness of 2 mm, a width of 50 mm, and a length of 100 mm at 0 ° C. , PP1300) so that the adhesive length is 75 mm. After backing the other surface of the double-sided adhesive tape with a PET film, a 2 kg roller was reciprocated once at 0 ° C. and pressure-bonded to prepare an adhesive test piece. The obtained adhesive test piece was left in an atmosphere of 0 ° C. for 60 minutes, then pulled in an environment of 0 ° C. at a tensile speed of 200 mm / min using an Instron tester, and peeled from the polypropylene plate at a peeling angle of 180 °. , The peel strength (N / 25 mm) was measured. Based on the result of peel strength, the low temperature stickability was evaluated according to the following evaluation criteria.
A: The peel strength is 5N / 25mm or more.
B: The peel strength is 3N / 25mm or more and less than 5N / 25mm.
C: Less than 3N / 25mm.

<PP adhesive strength>
One side of the double-sided adhesive tape cut to a width of 25 mm and a length of 100 mm according to JIS Z-1528 "Double-sided adhesive tape" is a polypropylene plate with a thickness of 2 mm, a width of 50 mm, and a length of 100 mm at 23 ° C. and 50% RH. It was bonded to (TP1300 manufactured by Takiron Co., Ltd.) so that the adhesive length was 75 mm. After backing the other surface of the double-sided adhesive tape with a PET film, a 2 kg roller was reciprocated once at 23 ° C. and 50% RH to crimp it to prepare an adhesive test piece. The obtained adhesive test piece was left to stand in an atmosphere of 23 ° C. and 50% RH for 20 minutes, then pulled at a tensile speed of 200 mm / min using an Instron tester, and peeled off from the polypropylene plate at a peeling angle of 180 °. , The peel strength (N / 25 mm) was measured at 23 ° C. Based on the result of peel strength, PP adhesive strength was evaluated according to the following evaluation criteria.
A: The peel strength is 15 N / 25 mm or more.
B: The peel strength is 10 N / 25 mm or more and less than 15 N / 25 mm.
C: The peel strength is less than 10 N / 25 mm.

<Holding power at high temperature>
According to JISZ-1528, one side of the double-sided adhesive tape cut to a width of 25 mm and a length of 100 mm is adhered to a cold-rolled stainless steel plate (SUS304 plate) having a thickness of 1.5 mm, a width of 25 mm and a length of 100 mm at 23 ° C. The length was 25 mm, and the double-sided adhesive tape having a length of 75 mm was attached by shifting in the length direction so as to protrude from the end of the SUS304 plate. Then, after backing the other side of the double-sided adhesive tape with a PET film, a 2 kg roller was reciprocated once and crimped to prepare an adhesive test piece.
After leaving the obtained adhesive test piece in an atmosphere of 23 ° C. and 50% RH for 20 minutes, the adhesive test piece is placed vertically on a constant temperature dryer at 40 ° C. with the protruding double-sided adhesive tape side facing down. I hung up for a while. Next, a load of 1 kg was applied to the lower end of the double-sided adhesive tape, and the tape was vertically suspended at 40 ° C. for 24 hours, and the deviation distance (mm) of the bonded portion after 1 hour was measured. The evaluation was based on the following evaluation criteria based on the deviation distance.
A: The deviation distance is less than 0.5 mm.
B: The deviation distance is 0.5 mm or more and less than 2 mm.
C: The deviation distance is 2 mm or more.

The components used in Examples and Comparative Examples are as follows.
<Monomer (A1)>
(Main monomer)
n-Heptyl acrylate (HA (C7)):
^{The n-heptyl acrylate is a compound in which R 2} is a biological carbon in the general formula (1), and was prepared by an esterification reaction between acrylic acid and n-heptyl alcohol. The n-heptyl alcohol was prepared by cracking ricinoleic acid derived from castor oil as a raw material.
(Comonomer)
2-Ethylhexyl acrylate (2EHA): manufactured by Mitsubishi Chemical Corporation <Other monomers>
Butyl acrylate (BA): Acrylic acid (AAc) manufactured by Mitsubishi Chemical Corporation: 2-Hydroxyethyl acrylate (HEA) manufactured by Nippon Shokubai Co., Ltd .: <Adhesive imparting agent (TF)> manufactured by Osaka Organic Chemical Industry Co., Ltd.
Polymerized rosin ester resin, hydroxyl value 46, softening point 150 ° C, biological carbon content 95% by mass
<Crosslinking agent>
Polyisocyanate cross-linking agent, manufactured by Tosoh Co., Ltd., "Coronate L-45"

(Example 1)
[Synthesis of polymer (X1)]
Ethyl acetate was added as a polymerization solvent to the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen to start reflux. Subsequently, a polymerization initiator solution obtained by diluting 0.1 parts by mass of azobisisobutyronitrile with ethyl acetate 10 times as a polymerization initiator was put into the reaction vessel, and n-heptyl acrylate (HA (C7)) 96. 9 parts by mass, 2.9 parts by mass of acrylic acid (AAc), and 0.2 parts by mass of 2-hydroxyethyl acrylate (HEA) were added dropwise over 2 hours. After completion of the dropwise addition, a polymerization initiator solution obtained by diluting 0.1 part by mass of azobisisobutyronitrile with ethyl acetate 10 times as a polymerization initiator was put into the reaction vessel again, and the polymerization reaction was carried out for 4 hours to carry out the polymerization reaction of the polymer (X1). ) The containing solution was obtained. The weight average molecular weight of the obtained polymer (X1) was measured and found to be 600,000.

[Making double-sided adhesive tape]
To 100 parts by mass of the polymer (X1), 0.8 parts by mass of the cross-linking agent and 15 parts by mass of the tackifier were added to the obtained polymer (X1) -containing solution to prepare a pressure-sensitive adhesive composition solution. The pressure-sensitive adhesive composition solution was applied to the peeled surface of the peeling sheet whose one side was peeled off, heated and dried to form a pressure-sensitive adhesive layer. The obtained pressure-sensitive adhesive layer was transferred to both sides of a non-woven fabric as a base material to obtain a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the base material.
The pressure-sensitive adhesive was collected from the pressure-sensitive adhesive layer of the obtained double-sided adhesive tape, and the degree of cross-linking and the bio-rate were measured. Further, a measurement sample was prepared from the pressure-sensitive adhesive composition solution, and the storage elastic modulus G', the loss elastic modulus G', and the glass transition temperature (Tg) were measured. The PP adhesive strength and the holding power under high temperature were evaluated. The evaluation results are shown in Table 2.

(Examples 2 and 3)
The same procedure as in Example 1 was carried out except that the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1.

(Example 4)
In the production of the polymer (X1), the same procedure as in Example 1 was carried out except that the polymerization reaction time was changed to 5 hours.

(Example 5)
In the production of the polymer (X1), the time of the polymerization reaction was changed to 5.5 hours. Further, the same procedure as in Example 1 was carried out except that the blending amount of the cross-linking agent was changed to the mass part shown in Table 1.

(Example 6)
Except that the blending amount of the monomer when preparing the polymer (X1) was changed to the ratio shown in Table 1, and the blending amount of the tackifier (TF) and the cross-linking agent was changed to the parts by mass shown in Table 1. It was carried out in the same manner as in Example 1.

(Comparative Example 1)
In the production of the polymer (X1), the time of the polymerization reaction was changed to 7 hours. Further, the same procedure as in Example 1 was carried out except that the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1.

(Comparative Example 2)
In the production of the polymer (X1), the time of the polymerization reaction was changed to 2.5 hours. Further, the same procedure as in Example 1 was carried out except that the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1.

(Comparative Example 3)
The type and amount of the monomer used to prepare the polymer (X1) were changed as shown in Table 1, and the amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1. It was carried out in the same manner as in Example 1 except that it was carried out.

* Molecular weight is the weight average molecular weight (Mw).
* The mass part of the monomer is a value when the total amount of the monomers blended when synthesizing the polymer (X1) is 100 parts by mass. The polymer (X1) can be considered to contain the structural units derived from each of the monomers listed in Table 1 in the amounts listed in Table 1.
* The blending amount of the tackifier (TF) and the cross-linking agent is parts by mass with respect to 100 parts by mass of the polymer (X1).

In each of the above examples, the pressure-sensitive adhesive contains a polymer (X1) containing a predetermined amount or more of a constituent unit derived from the monomer (A1), and tan δ (23 ° C.) is set to 0.8 to 1.3. The holding power at high temperature, the low-temperature stickability, and the adhesiveness to a low-polarity adherend (polypropylene resin) were all improved. On the other hand, in each comparative example, the polymer (X1) did not contain a predetermined amount or more of the structural unit derived from the monomer (A1), or tan δ (23 ° C.) was out of the range, so that the biorate was high. However, it was not possible to improve the holding power at high temperature, the low temperature stickability, and the adhesiveness to the low-polarity adherend (polypropylene resin).

<< Second Example >>
[Measurement and evaluation method]
The measurement and evaluation of each physical property were carried out as follows.
<Peak Top Molecular Weight (Mtp)>
The pressure-sensitive adhesive collected from the pressure-sensitive adhesive tape was dipped in tetrahydrofuran (THF) and shake-immersed at room temperature for 24 hours. Then, a sample of the above-mentioned pressure-sensitive adhesive was taken out with a 200-mesh filter, the immersion liquid was filtered with a filter, and the obtained filtrate was used as a sample solution containing a sol component of the above-mentioned pressure-sensitive adhesive. The obtained sample solution is supplied to gel permeation chromatography (GPC, for example, "e2695" manufactured by Waters), tetrahydrofuran (THF) is used as the mobile phase, the sample flow rate is 1 mL / min, and the column temperature is 40 ° C. The GPC measurement was performed in 1 and the molecular weight distribution of the polystyrene-equivalent molecular weight was measured. As the column, for example, two "GPC KF-806L" manufactured by shodex were connected in series and used. From the obtained molecular weight distribution curve, the peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by GPC was calculated. The peak due to GPC derived from the tackifier (TF) was not included. Therefore, the peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by GPC is the peak top molecular weight of the sol of the polymer which is the main component of the pressure-sensitive adhesive by GPC.

<Weight average molecular weight (Mw), dispersity (D), sol fraction (R _sol ) and hardness (S),>
In the same manner as the above-mentioned measurement of peak top molecular weight (Mtp), the weight average molecular weight and the number average molecular weight of the sol content of the pressure-sensitive adhesive were measured using GPC. Then, the obtained weight average molecular weight was divided by the number average molecular weight to calculate the dispersity (D) of the sol. In addition, the gel fraction was measured by the following method, and the gel fraction was subtracted from 100% by mass to calculate the _{sol fraction (R sol).} As described above, the hardness and softness (S) were calculated from the obtained weight average molecular weight (Mw), dispersity (D) and sol fraction (R _sol). The peak due to GPC derived from the tackifier (TF) was not included. Therefore, the weight average molecular weight (Mw) and the degree of dispersion (D) of the sol of the pressure-sensitive adhesive are the weight-average molecular weight and the degree of dispersion of the sol of the polymer which is the main component of the pressure-sensitive adhesive.

The pressure-sensitive adhesive (sample) was collected in W1 (g), and the insoluble matter when the collected sample was immersed in THF at 23 ° C. for 24 hours was filtered through a 200-mesh wire mesh. The residue on the wire mesh was dried under the condition of 110 ° C. for 1 hour, the mass W2 (g) after drying was measured, and the gel fraction was calculated by the following formula.
Gel fraction (mass%) = 100 x W2 / W1

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) was measured by the same method as the method for measuring the glass transition temperature (Tg) of the first example.

<Bio rate>
The biorate of the adhesive was measured according to ASTM 6866.

<Elastic modulus>
The storage elastic modulus G'and the loss elastic modulus G'at each temperature were measured under the same conditions as the method for measuring the elastic modulus of the first embodiment. The storage elastic modulus G'and the loss elastic modulus G at each temperature were measured. ", And Tan δ show only the results of some examples and comparative examples.

<PP adhesive strength>
The peel strength (N / 25 mm) at 23 ° C. was measured by the same method as the PP adhesive strength of the first example. Based on the result of peel strength, PP adhesive strength was evaluated according to the following evaluation criteria.
A: The peel strength is 13 N / 25 mm or more.
B: The peel strength is 10 N / 25 mm or more and less than 13 N / 25 mm.
C: The peel strength is less than 10 N / 25 mm.

<Holding power under high temperature>
The deviation distance (mm) of the bonded portion after 1 hour was measured by the same method as the holding force under high temperature of the first embodiment. The evaluation was based on the following evaluation criteria based on the deviation distance.
A: The deviation distance is 0.5 mm or less.
B: The deviation distance is more than 0.5 mm and less than 1 mm.
C: The deviation distance is 1 mm or more.

<Low temperature stickability>
The low temperature stickability was evaluated by the same method as the low temperature stickability of the first example.

The components used in Examples and Comparative Examples are as follows.
<Monomer (A2)>
(Main monomer)
n-Heptyl acrylate (HA (C7)):
n- heptyl acrylate, R ⁵ in the general formula (2) is a compound which is carbon derived from a plant, was prepared by an esterification reaction between acrylic acid n- heptyl alcohol. The n-heptyl alcohol was prepared by cracking ricinoleic acid derived from castor oil as a raw material.
<Other monomers>
Acrylic acid (AAc): 2-hydroxyethyl acrylate (HEA) manufactured by Nippon Shokubai Co., Ltd .: <Adhesive imparting agent (TF)> manufactured by Osaka Organic Chemical Industry Co., Ltd.
Polymerized rosin ester resin, hydroxyl value 46, softening point 150 ° C., plant-derived carbon content 95% by mass
<Crosslinking agent>
Polyisocyanate cross-linking agent

(Example 7)
[Synthesis of polymer (X2)]
Ethyl acetate was added as a polymerization solvent to the reaction vessel, and after bubbling with nitrogen, the reaction vessel was heated while flowing nitrogen to start reflux. Subsequently, a polymerization initiator solution obtained by diluting 0.1 parts by mass of azobisisobutyronitrile with ethyl acetate 10 times as a polymerization initiator was put into the reaction vessel, and n-heptyl acrylate (HA (C7)) 96. 9 parts by mass, 2.9 parts by mass of acrylic acid (AAc), and 0.2 parts by mass of 2-hydroxyethyl acrylate (HEA) were added dropwise over 2 hours. After completion of the dropping, a polymerization initiator solution obtained by diluting 0.1 part by mass of azobisisobutyronitrile with ethyl acetate 10 times as a polymerization initiator was put into the reaction vessel again, and the polymerization reaction was carried out for 3.5 hours to carry out the polymerization reaction. A (X2) -containing solution was obtained. The weight average molecular weight of the obtained polymer (X2) was measured and found to be 500,000.

[Making double-sided adhesive tape]
To 100 parts by mass of the polymer (X2), 25 parts by mass of the tackifier and 2.4 parts by mass of the cross-linking agent were added to the obtained polymer (X2) -containing solution to prepare a pressure-sensitive adhesive composition solution. The pressure-sensitive adhesive composition solution was applied to the peeled surface of the peeling sheet whose one side was peeled off, heated at 100 ° C. for 3 minutes and dried to form a pressure-sensitive adhesive layer. .. The obtained pressure-sensitive adhesive layer was transferred to both sides of a non-woven fabric as a base material to obtain a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the base material.
The adhesive was collected from the adhesive layer of the obtained double-sided adhesive tape, and the peak top molecular weight (Mtp), weight average molecular weight (Mw), dispersity (D), sol fraction (R _sol ), and hardness (S) were obtained. ) And the biorate were measured. In addition, a measurement sample was prepared from the pressure-sensitive adhesive composition solution, and the glass transition temperature (Tg) was measured. Further, using a double-sided adhesive tape, PP adhesive strength, holding power at high temperature, and low temperature stickability were evaluated. The evaluation results are shown in Table 2.

(Examples 8 and 9)
The same procedure as in Example 1 was carried out except that the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1.

(Examples 10 to 14)
In the production of the polymer (X2), the time of the polymerization reaction was changed to change the weight average molecular weight of the polymer (X2) from 500,000 to 800,000. Further, the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1. Other than that, it was carried out in the same manner as in Example 1.

(Examples 15 to 17)
In the production of the polymer (X2), the time of the polymerization reaction was changed to change the weight average molecular weight of the polymer (X2) from 500,000 to 1,000,000. Further, the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1. Other than that, it was carried out in the same manner as in Example 1.

(Comparative Example 4)
In the production of the polymer (X2), the time of the polymerization reaction was changed to change the weight average molecular weight of the polymer (X2) from 500,000 to 800,000. Further, the blending amount of the tackifier (TF) was changed to the mass part shown in Table 1. Other than that, it was carried out in the same manner as in Example 1.

(Comparative Example 5)
The same procedure as in Example 1 was carried out except that the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1.

(Comparative Example 6)
In the production of the polymer (X2), the time of the polymerization reaction was changed to change the weight average molecular weight of the polymer (X2) from 500,000 to 1.2 million. Further, the blending amounts of the tackifier (TF) and the cross-linking agent were changed to the parts by mass shown in Table 1. Other than that, it was carried out in the same manner as in Example 1.

(Comparative Example 7)
The procedure was carried out in the same manner as in Example 1 except that the blending amount of the cross-linking agent was changed to the mass part shown in Table 3.

* Molecular weight is the weight average molecular weight (Mw).
* The mass part of the monomer is a value when the total amount of the monomers blended when synthesizing the polymer (X2) is 100 parts by mass. The polymer (X2) can be considered to contain the structural units derived from each of the monomers listed in Table 1 in the amounts listed in Table 1.
* The blending amount of the tackifier (TF) and the cross-linking agent is parts by mass with respect to 100 parts by mass of the polymer (X2).

In each of the above examples, the peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by gel permeation chromatography (GPC) is 137,000 or more and 300,000 or less, and the sol content of the pressure-sensitive adhesive (R _sol ) is 90% by mass or less. The glass transition temperature (Tg) of the pressure-sensitive adhesive was 5 ° C. or lower. As a result, the adhesiveness to the low-polarity adherend (polypropylene resin), the holding power at high temperature, and the low-temperature sticking property were all good. On the other hand, in each comparative example, the peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by gel permeation chromatography (GPC) was out of the range of 137,000 or more and 300,000 or less, or the sol content of the pressure-sensitive adhesive (R _sol). ) Was higher than 90% by mass, or the glass transition temperature (Tg) of the pressure-sensitive adhesive was higher than 5 ° C. Therefore, it was not possible to improve the adhesiveness to the low-polarity adherend (polypropylene resin), the holding power at high temperature, and the low-temperature stickability while increasing the biorate.

Claims

A structural unit derived from at least one monomer (Y) selected from the group consisting of the monomer (A1) represented by the following general formula (1) and the monomer (B1) represented by the following general formula (2). Contains a polymer (X1) containing 48% by mass or more,
Assuming that the storage elastic modulus at 23 ° C. is G'(23 ° C.) and the loss elastic modulus is G "(23 ° C.), tan δ (23 ° C.) obtained by G" (23 ° C.) / G'(23 ° C.) is 0. .8-1.3 adhesives.

In formula (1), R 1 represents H or CH 3 , R 2 represents −C n H 2n + 1 , and n represents an integer of 7 to 14. In equation (2), R 3 represents −C (= O) C m H 2m + 1 , and m represents an integer of 6 to 13.
The pressure-sensitive adhesive according to claim 1, wherein the polymer (X1) has a weight average molecular weight of 200,000 to 1,000,000.
The pressure-sensitive adhesive according to claim 1 or 2, which has a degree of cross-linking of 10 to 70%.
The pressure-sensitive adhesive according to any one of claims 1 to 3, wherein the storage elastic modulus at 0 ° C. is G'(0 ° C.) and the log G'(0 ° C.) [Pa] is 5.0 to 6.5. ..
The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the storage elastic modulus at 23 ° C. is G'(23 ° C.) and the log G'(23 ° C.) [Pa] is 4.8 to 5.5. ..
It is described in any one of claims 1 to 5 that log G'(80 ° C.) [Pa] is 4.1 to 4.8, where G'(80 ° C.) is the storage elastic modulus at 80 ° C. Adhesive.
The pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the glass transition temperature (Tg) is 15 ° C. or lower.
The pressure-sensitive adhesive according to any one of claims 1 to 7, wherein the content of carbon derived from an organism is 40% by mass or more.
The pressure-sensitive adhesive according to any one of claims 1 to 8, further comprising a pressure-sensitive adhesive.
An adhesive tape provided with an adhesive layer made of the adhesive according to any one of claims 1 to 9.
The adhesive tape according to claim 10, further comprising a base material, wherein the pressure-sensitive adhesive layer is provided on at least one surface of the base material.
The adhesive tape according to claim 11, wherein the base material is any one selected from a non-woven fabric, a polyethylene terephthalate film, and a foam.
Fixing a component constituting an electric appliance or an in-vehicle member by using the adhesive according to any one of claims 1 to 9 or the adhesive tape according to any one of claims 10 to 12. Method.
The adhesive according to any one of claims 1 to 9 is provided.
The peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by gel permeation chromatography (GPC) is 137,000 or more and 300,000 or less.
The sol fraction (R sol ) of the pressure-sensitive adhesive is 90% by mass or less.
A pressure-sensitive adhesive sheet having a glass transition temperature (Tg) of the pressure-sensitive adhesive of 5 ° C. or lower.
An adhesive sheet containing an adhesive containing biological components.
The peak top molecular weight (Mtp) of the sol of the pressure-sensitive adhesive by gel permeation chromatography (GPC) is 137,000 or more and 300,000 or less.
The sol fraction (R sol ) of the pressure-sensitive adhesive is 90% by mass or less.
A pressure-sensitive adhesive sheet having a glass transition temperature (Tg) of the pressure-sensitive adhesive of 5 ° C. or lower.
The pressure-sensitive adhesive sheet according to claim 15, wherein the hardness and softness (S) represented by the following general formula (3) in the pressure-sensitive adhesive is 50,000 or more and 180,000 or less.
S = Mw × R sol / D (3)
In the formula (3), Mw represents the weight average molecular weight of the sol of the pressure-sensitive adhesive by GPC, R sol represents the sol content of the pressure-sensitive adhesive, and D represents the dispersity of the sol of the pressure-sensitive adhesive by GPC. Represent.
The pressure-sensitive adhesive sheet according to claim 15 or 16, wherein the dispersity (D) of the sol portion of the pressure-sensitive adhesive by GPC is 1.6 or more and less than 3.
The pressure-sensitive adhesive sheet according to any one of claims 15 to 17, wherein the weight average molecular weight (Mw) of the sol of the pressure-sensitive adhesive by GPC is 190,000 or more and 700,000 or less.
The pressure-sensitive adhesive sheet according to any one of claims 15 to 18, wherein the sol fraction (R sol ) of the pressure-sensitive adhesive is 45% by mass or more and 75% by mass or less.
The pressure-sensitive adhesive sheet according to any one of claims 15 to 19, wherein the glass transition temperature (Tg) of the pressure-sensitive adhesive is 2.5 ° C. or less.
The pressure-sensitive adhesive sheet according to any one of claims 15 to 20, wherein the bio-rate of the pressure-sensitive adhesive is 51% or more.
The pressure-sensitive adhesive is at least one monomer (Y2) selected from the group consisting of the monomer (A2) represented by the following general formula (4) and the monomer (B2) represented by the following general formula (5). The pressure-sensitive adhesive sheet according to any one of claims 15 to 21, which contains a polymer (X2) containing 48% by mass or more of the derived structural unit.

In formula (4), R 4 represents H or CH 3 , R 5 represents -C n H 2n + 1 , n represents an integer of 7 to 20, and in formula (5) R 6 represents -C (=). O) C m H represents 2m + 1 , and m represents an integer of 6 to 13.
The pressure-sensitive adhesive sheet according to claim 22, wherein the content of the structural unit derived from n-heptyl (meth) acrylate in the polymer (X2) is 48% by mass or more.
The adhesive according to any one of claims 1 to 9, the adhesive tape according to any one of claims 10 to 12, or the adhesive sheet according to any one of claims 14 to 23. Electrical appliances to prepare.
The adhesive according to any one of claims 1 to 9, the adhesive tape according to any one of claims 10 to 12, or the adhesive sheet according to any one of claims 14 to 23 is provided. In-vehicle member.